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mftb() is expensive and one can be avoided on nested guest dispatch.
If the time checking code distinguishes between the L0 timer and the
nested HV timer, then both can be tested in the same place with the
same mftb() value.
This also nicely illustrates the relationship between the L0 and nested
HV timers.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211123095231.1036501-45-npiggin@gmail.com
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Implement support for hash guests under hash host. This has to save and
restore the host SLB, and ensure that the MMU is off while switching
into the guest SLB.
POWER9 and later CPUs now always go via the P9 path. The "fast" guest
mode is now renamed to the P9 mode, which is consistent with its
functionality and the rest of the naming.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210528090752.3542186-32-npiggin@gmail.com
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Implement hash guest support. Guest entry/exit has to restore and
save/clear the SLB, plus several other bits to accommodate hash guests
in the P9 path. Radix host, hash guest support is removed from the P7/8
path.
The HPT hcalls and faults are not handled in real mode, which is a
performance regression. A worst-case fork/exit microbenchmark takes 3x
longer after this patch. kbuild benchmark performance is in the noise,
but the slowdown is likely to be noticed somewhere.
For now, accept this penalty for the benefit of simplifying the P7/8
paths and unifying P9 hash with the new code, because hash is a less
important configuration than radix on processors that support it. Hash
will benefit from future optimisations to this path, including possibly
a faster path to handle such hcalls and interrupts without doing a full
exit.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210528090752.3542186-31-npiggin@gmail.com
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Dependent-threads mode is the normal KVM mode for pre-POWER9 SMT
processors, where all threads in a core (or subcore) would run the same
partition at the same time, or they would run the host.
This design was mandated by MMU state that is shared between threads in
a processor, so the synchronisation point is in hypervisor real-mode
that has essentially no shared state, so it's safe for multiple threads
to gather and switch to the correct mode.
It is implemented by having the host unplug all secondary threads and
always run in SMT1 mode, and host QEMU threads essentially represent
virtual cores that wake these secondary threads out of unplug when the
ioctl is called to run the guest. This happens via a side-path that is
mostly invisible to the rest of the Linux host and the secondary threads
still appear to be unplugged.
POWER9 / ISA v3.0 has a more flexible MMU design that is independent
per-thread and allows a much simpler KVM implementation. Before the new
"P9 fast path" was added that began to take advantage of this, POWER9
support was implemented in the existing path which has support to run
in the dependent threads mode. So it was not much work to add support to
run POWER9 in this dependent threads mode.
The mode is not required by the POWER9 MMU (although "mixed-mode" hash /
radix MMU limitations of early processors were worked around using this
mode). But it is one way to run SMT guests without running different
guests or guest and host on different threads of the same core, so it
could avoid or reduce some SMT attack surfaces without turning off SMT
entirely.
This security feature has some real, if indeterminate, value. However
the old path is lagging in features (nested HV), and with this series
the new P9 path adds remaining missing features (radix prefetch bug
and hash support, in later patches), so POWER9 dependent threads mode
support would be the only remaining reason to keep that code in and keep
supporting POWER9/POWER10 in the old path. So here we make the call to
drop this feature.
Remove dependent threads mode support for POWER9 and above processors.
Systems can still achieve this security by disabling SMT entirely, but
that would generally come at a larger performance cost for guests.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210528090752.3542186-23-npiggin@gmail.com
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Almost all logic is moved to C, by introducing a new in_guest mode for
the P9 path that branches very early in the KVM interrupt handler to P9
exit code.
The main P9 entry and exit assembly is now only about 160 lines of low
level stack setup and register save/restore, plus a bad-interrupt
handler.
There are two motivations for this, the first is just make the code more
maintainable being in C. The second is to reduce the amount of code
running in a special KVM mode, "realmode". In quotes because with radix
it is no longer necessarily real-mode in the MMU, but it still has to be
treated specially because it may be in real-mode, and has various
important registers like PID, DEC, TB, etc set to guest. This is hostile
to the rest of Linux and can't use arbitrary kernel functionality or be
instrumented well.
This initial patch is a reasonably faithful conversion of the asm code,
but it does lack any loop to return quickly back into the guest without
switching out of realmode in the case of unimportant or easily handled
interrupts. As explained in previous changes, handling HV interrupts
very quickly in this low level realmode is not so important for P9
performance, and are important to avoid for security, observability,
debugability reasons.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210528090752.3542186-15-npiggin@gmail.com
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On P9 DD2.2 due to a CPU defect some TM instructions need to be emulated by
KVM. This is handled at first by the hardware raising a softpatch interrupt
when certain TM instructions that need KVM assistance are executed in the
guest. Althought some TM instructions per Power ISA are invalid forms they
can raise a softpatch interrupt too. For instance, 'tresume.' instruction
as defined in the ISA must have bit 31 set (1), but an instruction that
matches 'tresume.' PO and XO opcode fields but has bit 31 not set (0), like
0x7cfe9ddc, also raises a softpatch interrupt. Similarly for 'treclaim.'
and 'trechkpt.' instructions with bit 31 = 0, i.e. 0x7c00075c and
0x7c0007dc, respectively. Hence, if a code like the following is executed
in the guest it will raise a softpatch interrupt just like a 'tresume.'
when the TM facility is enabled ('tabort. 0' in the example is used only
to enable the TM facility):
int main() { asm("tabort. 0; .long 0x7cfe9ddc;"); }
Currently in such a case KVM throws a complete trace like:
[345523.705984] WARNING: CPU: 24 PID: 64413 at arch/powerpc/kvm/book3s_hv_tm.c:211 kvmhv_p9_tm_emulation+0x68/0x620 [kvm_hv]
[345523.705985] Modules linked in: kvm_hv(E) xt_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp ip6table_mangle ip6table_nat
iptable_mangle iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ebtable_filter ebtables ip6table_filter
ip6_tables iptable_filter bridge stp llc sch_fq_codel ipmi_powernv at24 vmx_crypto ipmi_devintf ipmi_msghandler
ibmpowernv uio_pdrv_genirq kvm opal_prd uio leds_powernv ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp
libiscsi scsi_transport_iscsi ip_tables x_tables autofs4 btrfs blake2b_generic zstd_compress raid10 raid456
async_raid6_recov async_memcpy async_pq async_xor async_tx libcrc32c xor raid6_pq raid1 raid0 multipath linear tg3
crct10dif_vpmsum crc32c_vpmsum ipr [last unloaded: kvm_hv]
[345523.706030] CPU: 24 PID: 64413 Comm: CPU 0/KVM Tainted: G W E 5.5.0+ #1
[345523.706031] NIP: c0080000072cb9c0 LR: c0080000072b5e80 CTR: c0080000085c7850
[345523.706034] REGS: c000000399467680 TRAP: 0700 Tainted: G W E (5.5.0+)
[345523.706034] MSR: 900000010282b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE,TM[E]> CR: 24022428 XER: 00000000
[345523.706042] CFAR: c0080000072b5e7c IRQMASK: 0
GPR00: c0080000072b5e80 c000000399467910 c0080000072db500 c000000375ccc720
GPR04: c000000375ccc720 00000003fbec0000 0000a10395dda5a6 0000000000000000
GPR08: 000000007cfe9ddc 7cfe9ddc000005dc 7cfe9ddc7c0005dc c0080000072cd530
GPR12: c0080000085c7850 c0000003fffeb800 0000000000000001 00007dfb737f0000
GPR16: c0002001edcca558 0000000000000000 0000000000000000 0000000000000001
GPR20: c000000001b21258 c0002001edcca558 0000000000000018 0000000000000000
GPR24: 0000000001000000 ffffffffffffffff 0000000000000001 0000000000001500
GPR28: c0002001edcc4278 c00000037dd80000 800000050280f033 c000000375ccc720
[345523.706062] NIP [c0080000072cb9c0] kvmhv_p9_tm_emulation+0x68/0x620 [kvm_hv]
[345523.706065] LR [c0080000072b5e80] kvmppc_handle_exit_hv.isra.53+0x3e8/0x798 [kvm_hv]
[345523.706066] Call Trace:
[345523.706069] [c000000399467910] [c000000399467940] 0xc000000399467940 (unreliable)
[345523.706071] [c000000399467950] [c000000399467980] 0xc000000399467980
[345523.706075] [c0000003994679f0] [c0080000072bd1c4] kvmhv_run_single_vcpu+0xa1c/0xb80 [kvm_hv]
[345523.706079] [c000000399467ac0] [c0080000072bd8e0] kvmppc_vcpu_run_hv+0x5b8/0xb00 [kvm_hv]
[345523.706087] [c000000399467b90] [c0080000085c93cc] kvmppc_vcpu_run+0x34/0x48 [kvm]
[345523.706095] [c000000399467bb0] [c0080000085c582c] kvm_arch_vcpu_ioctl_run+0x244/0x420 [kvm]
[345523.706101] [c000000399467c40] [c0080000085b7498] kvm_vcpu_ioctl+0x3d0/0x7b0 [kvm]
[345523.706105] [c000000399467db0] [c0000000004adf9c] ksys_ioctl+0x13c/0x170
[345523.706107] [c000000399467e00] [c0000000004adff8] sys_ioctl+0x28/0x80
[345523.706111] [c000000399467e20] [c00000000000b278] system_call+0x5c/0x68
[345523.706112] Instruction dump:
[345523.706114] 419e0390 7f8a4840 409d0048 6d497c00 2f89075d 419e021c 6d497c00 2f8907dd
[345523.706119] 419e01c0 6d497c00 2f8905dd 419e00a4 <0fe00000> 38210040 38600000 ebc1fff0
and then treats the executed instruction as a 'nop'.
However the POWER9 User's Manual, in section "4.6.10 Book II Invalid
Forms", informs that for TM instructions bit 31 is in fact ignored, thus
for the TM-related invalid forms ignoring bit 31 and handling them like the
valid forms is an acceptable way to handle them. POWER8 behaves the same
way too.
This commit changes the handling of the cases here described by treating
the TM-related invalid forms that can generate a softpatch interrupt
just like their valid forms (w/ bit 31 = 1) instead of as a 'nop' and by
gently reporting any other unrecognized case to the host and treating it as
illegal instruction instead of throwing a trace and treating it as a 'nop'.
Signed-off-by: Gustavo Romero <gromero@linux.ibm.com>
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Acked-By: Michael Neuling <mikey@neuling.org>
Reviewed-by: Leonardo Bras <leonardo@linux.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
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Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not write to the free
software foundation 51 franklin street fifth floor boston ma 02110
1301 usa
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 67 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141333.953658117@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Currently we use two bits in the vcpu pending_exceptions bitmap to
indicate that an external interrupt is pending for the guest, one
for "one-shot" interrupts that are cleared when delivered, and one
for interrupts that persist until cleared by an explicit action of
the OS (e.g. an acknowledge to an interrupt controller). The
BOOK3S_IRQPRIO_EXTERNAL bit is used for one-shot interrupt requests
and BOOK3S_IRQPRIO_EXTERNAL_LEVEL is used for persisting interrupts.
In practice BOOK3S_IRQPRIO_EXTERNAL never gets used, because our
Book3S platforms generally, and pseries in particular, expect
external interrupt requests to persist until they are acknowledged
at the interrupt controller. That combined with the confusion
introduced by having two bits for what is essentially the same thing
makes it attractive to simplify things by only using one bit. This
patch does that.
With this patch there is only BOOK3S_IRQPRIO_EXTERNAL, and by default
it has the semantics of a persisting interrupt. In order to avoid
breaking the ABI, we introduce a new "external_oneshot" flag which
preserves the behaviour of the KVM_INTERRUPT ioctl with the
KVM_INTERRUPT_SET argument.
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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POWER9 has hardware bugs relating to transactional memory and thread
reconfiguration (changes to hardware SMT mode). Specifically, the core
does not have enough storage to store a complete checkpoint of all the
architected state for all four threads. The DD2.2 version of POWER9
includes hardware modifications designed to allow hypervisor software
to implement workarounds for these problems. This patch implements
those workarounds in KVM code so that KVM guests see a full, working
transactional memory implementation.
The problems center around the use of TM suspended state, where the
CPU has a checkpointed state but execution is not transactional. The
workaround is to implement a "fake suspend" state, which looks to the
guest like suspended state but the CPU does not store a checkpoint.
In this state, any instruction that would cause a transition to
transactional state (rfid, rfebb, mtmsrd, tresume) or would use the
checkpointed state (treclaim) causes a "soft patch" interrupt (vector
0x1500) to the hypervisor so that it can be emulated. The trechkpt
instruction also causes a soft patch interrupt.
On POWER9 DD2.2, we avoid returning to the guest in any state which
would require a checkpoint to be present. The trechkpt in the guest
entry path which would normally create that checkpoint is replaced by
either a transition to fake suspend state, if the guest is in suspend
state, or a rollback to the pre-transactional state if the guest is in
transactional state. Fake suspend state is indicated by a flag in the
PACA plus a new bit in the PSSCR. The new PSSCR bit is write-only and
reads back as 0.
On exit from the guest, if the guest is in fake suspend state, we still
do the treclaim instruction as we would in real suspend state, in order
to get into non-transactional state, but we do not save the resulting
register state since there was no checkpoint.
Emulation of the instructions that cause a softpatch interrupt is
handled in two paths. If the guest is in real suspend mode, we call
kvmhv_p9_tm_emulation_early() to handle the cases where the guest is
transitioning to transactional state. This is called before we do the
treclaim in the guest exit path; because we haven't done treclaim, we
can get back to the guest with the transaction still active. If the
instruction is a case that kvmhv_p9_tm_emulation_early() doesn't
handle, or if the guest is in fake suspend state, then we proceed to
do the complete guest exit path and subsequently call
kvmhv_p9_tm_emulation() in host context with the MMU on. This handles
all the cases including the cases that generate program interrupts
(illegal instruction or TM Bad Thing) and facility unavailable
interrupts.
The emulation is reasonably straightforward and is mostly concerned
with checking for exception conditions and updating the state of
registers such as MSR and CR0. The treclaim emulation takes care to
ensure that the TEXASR register gets updated as if it were the guest
treclaim instruction that had done failure recording, not the treclaim
done in hypervisor state in the guest exit path.
With this, the KVM_CAP_PPC_HTM capability returns true (1) even if
transactional memory is not available to host userspace.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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The new XIVE interrupt controller on POWER9 can direct external
interrupts to the hypervisor or the guest. The interrupts directed to
the hypervisor are controlled by an LPCR bit called LPCR_HVICE, and
come in as a "hypervisor virtualization interrupt". This sets the
LPCR bit so that hypervisor virtualization interrupts can occur while
we are in the guest. We then also need to cope with exiting the guest
because of a hypervisor virtualization interrupt.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
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In existing real mode ICP code, when updating the virtual ICP
state, if there is a required action that cannot be completely
handled in real mode, as for instance, a VCPU needs to be woken
up, flags are set in the ICP to indicate the required action.
This is checked when returning from hypercalls to decide whether
the call needs switch back to the host where the action can be
performed in virtual mode. Note that if h_ipi_redirect is enabled,
real mode code will first try to message a free host CPU to
complete this job instead of returning the host to do it ourselves.
Currently, the real mode PCI passthrough interrupt handling code
checks if any of these flags are set and simply returns to the host.
This is not good enough as the trap value (0x500) is treated as an
external interrupt by the host code. It is only when the trap value
is a hypercall that the host code searches for and acts on unfinished
work by calling kvmppc_xics_rm_complete.
This patch introduces a special trap BOOK3S_INTERRUPT_HV_RM_HARD
which is returned by KVM if there is unfinished business to be
completed in host virtual mode after handling a PCI passthrough
interrupt. The host checks for this special interrupt condition
and calls into the kvmppc_xics_rm_complete, which is made an
exported function for this reason.
[paulus@ozlabs.org - moved logic to set r12 to BOOK3S_INTERRUPT_HV_RM_HARD
in book3s_hv_rmhandlers.S into the end of kvmppc_check_wake_reason.]
Signed-off-by: Suresh Warrier <warrier@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
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We currently decide at compile-time which of the SPE or AltiVec units to
support exclusively. Guard kernel defines with CONFIG_SPE_POSSIBLE and
CONFIG_PPC_E500MC and remove shared defines.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
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Pull second round of KVM changes from Paolo Bonzini:
"Here are the PPC and ARM changes for KVM, which I separated because
they had small conflicts (respectively within KVM documentation, and
with 3.16-rc changes). Since they were all within the subsystem, I
took care of them.
Stephen Rothwell reported some snags in PPC builds, but they are all
fixed now; the latest linux-next report was clean.
New features for ARM include:
- KVM VGIC v2 emulation on GICv3 hardware
- Big-Endian support for arm/arm64 (guest and host)
- Debug Architecture support for arm64 (arm32 is on Christoffer's todo list)
And for PPC:
- Book3S: Good number of LE host fixes, enable HV on LE
- Book3S HV: Add in-guest debug support
This release drops support for KVM on the PPC440. As a result, the
PPC merge removes more lines than it adds. :)
I also included an x86 change, since Davidlohr tied it to an
independent bug report and the reporter quickly provided a Tested-by;
there was no reason to wait for -rc2"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (122 commits)
KVM: Move more code under CONFIG_HAVE_KVM_IRQFD
KVM: nVMX: fix "acknowledge interrupt on exit" when APICv is in use
KVM: nVMX: Fix nested vmexit ack intr before load vmcs01
KVM: PPC: Enable IRQFD support for the XICS interrupt controller
KVM: Give IRQFD its own separate enabling Kconfig option
KVM: Move irq notifier implementation into eventfd.c
KVM: Move all accesses to kvm::irq_routing into irqchip.c
KVM: irqchip: Provide and use accessors for irq routing table
KVM: Don't keep reference to irq routing table in irqfd struct
KVM: PPC: drop duplicate tracepoint
arm64: KVM: fix 64bit CP15 VM access for 32bit guests
KVM: arm64: GICv3: mandate page-aligned GICV region
arm64: KVM: GICv3: move system register access to msr_s/mrs_s
KVM: PPC: PR: Handle FSCR feature deselects
KVM: PPC: HV: Remove generic instruction emulation
KVM: PPC: BOOKEHV: rename e500hv_spr to bookehv_spr
KVM: PPC: Remove DCR handling
KVM: PPC: Expose helper functions for data/inst faults
KVM: PPC: Separate loadstore emulation from priv emulation
KVM: PPC: Handle magic page in kvmppc_ld/st
...
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Handle Hypervisor Maintenance Interrupt (HMI) in Linux. This patch implements
basic infrastructure to handle HMI in Linux host. The design is to invoke
opal handle hmi in real mode for recovery and set irq_pending when we hit HMI.
During check_irq_replay pull opal hmi event and print hmi info on console.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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The 440 target hasn't been properly functioning for a few releases and
before I was the only one who fixes a very serious bug that indicates to
me that nobody used it before either.
Furthermore KVM on 440 is slow to the extent of unusable.
We don't have to carry along completely unused code. Remove 440 and give
us one less thing to worry about.
Signed-off-by: Alexander Graf <agraf@suse.de>
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Today we handle split real mode by mapping both instruction and data faults
into a special virtual address space that only exists during the split mode
phase.
This is good enough to catch 32bit Linux guests that use split real mode for
copy_from/to_user. In this case we're always prefixed with 0xc0000000 for our
instruction pointer and can map the user space process freely below there.
However, that approach fails when we're running KVM inside of KVM. Here the 1st
level last_inst reader may well be in the same virtual page as a 2nd level
interrupt handler.
It also fails when running Mac OS X guests. Here we have a 4G/4G split, so a
kernel copy_from/to_user implementation can easily overlap with user space
addresses.
The architecturally correct way to fix this would be to implement an instruction
interpreter in KVM that kicks in whenever we go into split real mode. This
interpreter however would not receive a great amount of testing and be a lot of
bloat for a reasonably isolated corner case.
So I went back to the drawing board and tried to come up with a way to make
split real mode work with a single flat address space. And then I realized that
we could get away with the same trick that makes it work for Linux:
Whenever we see an instruction address during split real mode that may collide,
we just move it higher up the virtual address space to a place that hopefully
does not collide (keep your fingers crossed!).
That approach does work surprisingly well. I am able to successfully run
Mac OS X guests with KVM and QEMU (no split real mode hacks like MOL) when I
apply a tiny timing probe hack to QEMU. I'd say this is a win over even more
broken split real mode :).
Signed-off-by: Alexander Graf <agraf@suse.de>
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POWER8 introduced a new interrupt type called "Facility unavailable interrupt"
which contains its status message in a new register called FSCR.
Handle these exits and try to emulate instructions for unhandled facilities.
Follow-on patches enable KVM to expose specific facilities into the guest.
Signed-off-by: Alexander Graf <agraf@suse.de>
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Pull more KVM updates from Paolo Bonzini:
"Second batch of KVM updates. Some minor x86 fixes, two s390 guest
features that need some handling in the host, and all the PPC changes.
The PPC changes include support for little-endian guests and
enablement for new POWER8 features"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (45 commits)
x86, kvm: correctly access the KVM_CPUID_FEATURES leaf at 0x40000101
x86, kvm: cache the base of the KVM cpuid leaves
kvm: x86: move KVM_CAP_HYPERV_TIME outside #ifdef
KVM: PPC: Book3S PR: Cope with doorbell interrupts
KVM: PPC: Book3S HV: Add software abort codes for transactional memory
KVM: PPC: Book3S HV: Add new state for transactional memory
powerpc/Kconfig: Make TM select VSX and VMX
KVM: PPC: Book3S HV: Basic little-endian guest support
KVM: PPC: Book3S HV: Add support for DABRX register on POWER7
KVM: PPC: Book3S HV: Prepare for host using hypervisor doorbells
KVM: PPC: Book3S HV: Handle new LPCR bits on POWER8
KVM: PPC: Book3S HV: Handle guest using doorbells for IPIs
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap
KVM: PPC: Book3S HV: Implement architecture compatibility modes for POWER8
KVM: PPC: Book3S HV: Add handler for HV facility unavailable
KVM: PPC: Book3S HV: Flush the correct number of TLB sets on POWER8
KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers
KVM: PPC: Book3S HV: Don't set DABR on POWER8
kvm/ppc: IRQ disabling cleanup
...
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When the PR host is running on a POWER8 machine in POWER8 mode, it
will use doorbell interrupts for IPIs. If one of them arrives while
we are in the guest, we pop out of the guest with trap number 0xA00,
which isn't handled by kvmppc_handle_exit_pr, leading to the following
BUG_ON:
[ 331.436215] exit_nr=0xa00 | pc=0x1d2c | msr=0x800000000000d032
[ 331.437522] ------------[ cut here ]------------
[ 331.438296] kernel BUG at arch/powerpc/kvm/book3s_pr.c:982!
[ 331.439063] Oops: Exception in kernel mode, sig: 5 [#2]
[ 331.439819] SMP NR_CPUS=1024 NUMA pSeries
[ 331.440552] Modules linked in: tun nf_conntrack_netbios_ns nf_conntrack_broadcast ipt_MASQUERADE ip6t_REJECT xt_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw virtio_net kvm binfmt_misc ibmvscsi scsi_transport_srp scsi_tgt virtio_blk
[ 331.447614] CPU: 11 PID: 1296 Comm: qemu-system-ppc Tainted: G D 3.11.7-200.2.fc19.ppc64p7 #1
[ 331.448920] task: c0000003bdc8c000 ti: c0000003bd32c000 task.ti: c0000003bd32c000
[ 331.450088] NIP: d0000000025d6b9c LR: d0000000025d6b98 CTR: c0000000004cfdd0
[ 331.451042] REGS: c0000003bd32f420 TRAP: 0700 Tainted: G D (3.11.7-200.2.fc19.ppc64p7)
[ 331.452331] MSR: 800000000282b032 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI> CR: 28004824 XER: 20000000
[ 331.454616] SOFTE: 1
[ 331.455106] CFAR: c000000000848bb8
[ 331.455726]
GPR00: d0000000025d6b98 c0000003bd32f6a0 d0000000026017b8 0000000000000032
GPR04: c0000000018627f8 c000000001873208 320d0a3030303030 3030303030643033
GPR08: c000000000c490a8 0000000000000000 0000000000000000 0000000000000002
GPR12: 0000000028004822 c00000000fdc6300 0000000000000000 00000100076ec310
GPR16: 000000002ae343b8 00003ffffd397398 0000000000000000 0000000000000000
GPR20: 00000100076f16f4 00000100076ebe60 0000000000000008 ffffffffffffffff
GPR24: 0000000000000000 0000008001041e60 0000000000000000 0000008001040ce8
GPR28: c0000003a2d80000 0000000000000a00 0000000000000001 c0000003a2681810
[ 331.466504] NIP [d0000000025d6b9c] .kvmppc_handle_exit_pr+0x75c/0xa80 [kvm]
[ 331.466999] LR [d0000000025d6b98] .kvmppc_handle_exit_pr+0x758/0xa80 [kvm]
[ 331.467517] Call Trace:
[ 331.467909] [c0000003bd32f6a0] [d0000000025d6b98] .kvmppc_handle_exit_pr+0x758/0xa80 [kvm] (unreliable)
[ 331.468553] [c0000003bd32f750] [d0000000025d98f0] kvm_start_lightweight+0xb4/0xc4 [kvm]
[ 331.469189] [c0000003bd32f920] [d0000000025d7648] .kvmppc_vcpu_run_pr+0xd8/0x270 [kvm]
[ 331.469838] [c0000003bd32f9c0] [d0000000025cf748] .kvmppc_vcpu_run+0xc8/0xf0 [kvm]
[ 331.470790] [c0000003bd32fa50] [d0000000025cc19c] .kvm_arch_vcpu_ioctl_run+0x5c/0x1b0 [kvm]
[ 331.471401] [c0000003bd32fae0] [d0000000025c4888] .kvm_vcpu_ioctl+0x478/0x730 [kvm]
[ 331.472026] [c0000003bd32fc90] [c00000000026192c] .do_vfs_ioctl+0x4dc/0x7a0
[ 331.472561] [c0000003bd32fd80] [c000000000261cc4] .SyS_ioctl+0xd4/0xf0
[ 331.473095] [c0000003bd32fe30] [c000000000009ed8] syscall_exit+0x0/0x98
[ 331.473633] Instruction dump:
[ 331.473766] 4bfff9b4 2b9d0800 419efc18 60000000 60420000 3d220000 e8bf11a0 e8df12a8
[ 331.474733] 7fa4eb78 e8698660 48015165 e8410028 <0fe00000> 813f00e4 3ba00000 39290001
[ 331.475386] ---[ end trace 49fc47d994c1f8f2 ]---
[ 331.479817]
This fixes the problem by making kvmppc_handle_exit_pr() recognize the
interrupt. We also need to jump to the doorbell interrupt handler in
book3s_segment.S to handle the interrupt on the way out of the guest.
Having done that, there's nothing further to be done in
kvmppc_handle_exit_pr().
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
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POWER8 has support for hypervisor doorbell interrupts. Though the
kernel doesn't use them for IPIs on the powernv platform yet, it
probably will in future, so this makes KVM cope gracefully if a
hypervisor doorbell interrupt arrives while in a guest.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
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At present this should never happen, since the host kernel sets
HFSCR to allow access to all facilities. It's better to be prepared
to handle it cleanly if it does ever happen, though.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
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LRAT (Logical to Real Address Translation) present in MMU v2 provides hardware
translation from a logical page number (LPN) to a real page number (RPN) when
tlbwe is executed by a guest or when a page table translation occurs from a
guest virtual address.
Add LRAT error exception handler to Booke3E 64-bit kernel and the basic KVM
handler to avoid build breakage. This is a prerequisite for KVM LRAT support
that will follow.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
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When an interrupt or exception happens in the guest that comes to the
host, the CPU goes to hypervisor real mode (MMU off) to handle the
exception but doesn't change the MMU context. After saving a few
registers, we then clear the "in guest" flag. If, for any reason,
we get an exception in the real-mode code, that then gets handled
by the normal kernel exception handlers, which turn the MMU on. This
is disastrous if the MMU is still set to the guest context, since we
end up executing instructions from random places in the guest kernel
with hypervisor privilege.
In order to catch this situation, we define a new value for the "in guest"
flag, KVM_GUEST_MODE_HOST_HV, to indicate that we are in hypervisor real
mode with guest MMU context. If the "in guest" flag is set to this value,
we branch off to an emergency handler. For the moment, this just does
a branch to self to stop the CPU from doing anything further.
While we're here, we define another new flag value to indicate that we
are in a HV guest, as distinct from a PR guest. This will be useful
when we have a kernel that can support both PR and HV guests concurrently.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
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This adds the code to interpret 64k HPTEs in the guest hashed page
table (HPT), 64k SLB entries, and to tell the guest about 64k pages
in kvm_vm_ioctl_get_smmu_info(). Guest 64k pages are still shadowed
by 4k pages.
This also adds another hash table to the four we have already in
book3s_mmu_hpte.c to allow us to find all the PTEs that we have
instantiated that match a given 64k guest page.
The tlbie instruction changed starting with POWER6 to use a bit in
the RB operand to indicate large page invalidations, and to use other
RB bits to indicate the base and actual page sizes and the segment
size. 64k pages came in slightly earlier, with POWER5++.
We use one bit in vcpu->arch.hflags to indicate that the emulated
cpu supports 64k pages, and another to indicate that it has the new
tlbie definition.
The KVM_PPC_GET_SMMU_INFO ioctl presents a bit of a problem, because
the MMU capabilities depend on which CPU model we're emulating, but it
is a VM ioctl not a VCPU ioctl and therefore doesn't get passed a VCPU
fd. In addition, commonly-used userspace (QEMU) calls it before
setting the PVR for any VCPU. Therefore, as a best effort we look at
the first vcpu in the VM and return 64k pages or not depending on its
capabilities. We also make the PVR default to the host PVR on recent
CPUs that support 1TB segments (and therefore multiple page sizes as
well) so that KVM_PPC_GET_SMMU_INFO will include 64k page and 1TB
segment support on those CPUs.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
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Interrupt numbers defined for Book3E follows IVORs definition. Align
BOOKE_INTERRUPT_ALTIVEC_UNAVAIL and BOOKE_INTERRUPT_ALTIVEC_ASSIST to this
rule which also fixes the build breakage.
IVORs 32 and 33 are shared so reflect this in the interrupts naming.
This fixes a build break for 64-bit booke KVM.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
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The e6500 core adds support for AltiVec on a Book-E class processor.
Connect up all the various exception handling code and build config
mechanisms to allow user spaces apps to utilize AltiVec.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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There were a few places where we were traversing the list of runnable
threads in a virtual core, i.e. vc->runnable_threads, without holding
the vcore spinlock. This extends the places where we hold the vcore
spinlock to cover everywhere that we traverse that list.
Since we possibly need to sleep inside kvmppc_book3s_hv_page_fault,
this moves the call of it from kvmppc_handle_exit out to
kvmppc_vcpu_run, where we don't hold the vcore lock.
In kvmppc_vcore_blocked, we don't actually need to check whether
all vcpus are ceded and don't have any pending exceptions, since the
caller has already done that. The caller (kvmppc_run_vcpu) wasn't
actually checking for pending exceptions, so we add that.
The change of if to while in kvmppc_run_vcpu is to make sure that we
never call kvmppc_remove_runnable() when the vcore state is RUNNING or
EXITING.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
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We only want asm code macros to be accessible from asm code, so #ifdef it
depending on it.
Signed-off-by: Alexander Graf <agraf@suse.de>
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Introduced PPC_STD/PPC_LD macros for saving/restoring guest registers to/from their 64 bit copies.
Signed-off-by: Varun Sethi <Varun.Sethi@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
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Chips such as e500mc that implement category E.HV in Power ISA 2.06
provide hardware virtualization features, including a new MSR mode for
guest state. The guest OS can perform many operations without trapping
into the hypervisor, including transitions to and from guest userspace.
Since we can use SRR1[GS] to reliably tell whether an exception came from
guest state, instead of messing around with IVPR, we use DO_KVM similarly
to book3s.
Current issues include:
- Machine checks from guest state are not routed to the host handler.
- The guest can cause a host oops by executing an emulated instruction
in a page that lacks read permission. Existing e500/4xx support has
the same problem.
Includes work by Ashish Kalra <Ashish.Kalra@freescale.com>,
Varun Sethi <Varun.Sethi@freescale.com>, and
Liu Yu <yu.liu@freescale.com>.
Signed-off-by: Scott Wood <scottwood@freescale.com>
[agraf: remove pt_regs usage]
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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This adds support for KVM running on 64-bit Book 3S processors,
specifically POWER7, in hypervisor mode. Using hypervisor mode means
that the guest can use the processor's supervisor mode. That means
that the guest can execute privileged instructions and access privileged
registers itself without trapping to the host. This gives excellent
performance, but does mean that KVM cannot emulate a processor
architecture other than the one that the hardware implements.
This code assumes that the guest is running paravirtualized using the
PAPR (Power Architecture Platform Requirements) interface, which is the
interface that IBM's PowerVM hypervisor uses. That means that existing
Linux distributions that run on IBM pSeries machines will also run
under KVM without modification. In order to communicate the PAPR
hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code
to include/linux/kvm.h.
Currently the choice between book3s_hv support and book3s_pr support
(i.e. the existing code, which runs the guest in user mode) has to be
made at kernel configuration time, so a given kernel binary can only
do one or the other.
This new book3s_hv code doesn't support MMIO emulation at present.
Since we are running paravirtualized guests, this isn't a serious
restriction.
With the guest running in supervisor mode, most exceptions go straight
to the guest. We will never get data or instruction storage or segment
interrupts, alignment interrupts, decrementer interrupts, program
interrupts, single-step interrupts, etc., coming to the hypervisor from
the guest. Therefore this introduces a new KVMTEST_NONHV macro for the
exception entry path so that we don't have to do the KVM test on entry
to those exception handlers.
We do however get hypervisor decrementer, hypervisor data storage,
hypervisor instruction storage, and hypervisor emulation assist
interrupts, so we have to handle those.
In hypervisor mode, real-mode accesses can access all of RAM, not just
a limited amount. Therefore we put all the guest state in the vcpu.arch
and use the shadow_vcpu in the PACA only for temporary scratch space.
We allocate the vcpu with kzalloc rather than vzalloc, and we don't use
anything in the kvmppc_vcpu_book3s struct, so we don't allocate it.
We don't have a shared page with the guest, but we still need a
kvm_vcpu_arch_shared struct to store the values of various registers,
so we include one in the vcpu_arch struct.
The POWER7 processor has a restriction that all threads in a core have
to be in the same partition. MMU-on kernel code counts as a partition
(partition 0), so we have to do a partition switch on every entry to and
exit from the guest. At present we require the host and guest to run
in single-thread mode because of this hardware restriction.
This code allocates a hashed page table for the guest and initializes
it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We
require that the guest memory is allocated using 16MB huge pages, in
order to simplify the low-level memory management. This also means that
we can get away without tracking paging activity in the host for now,
since huge pages can't be paged or swapped.
This also adds a few new exports needed by the book3s_hv code.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
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Pass the register type to the prolog, also provides alternate "HV"
version of hardware interrupt (0x500) and adjust LPES accordingly
We tag those interrupts by setting bit 0x2 in the trap number
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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The current interrupt logic is just completely broken. We get a notification
from user space, telling us that an interrupt is there. But then user space
expects us that we just acknowledge an interrupt once we deliver it to the
guest.
This is not how real hardware works though. On real hardware, the interrupt
controller pulls the external interrupt line until it gets notified that the
interrupt was received.
So in reality we have two events: pulling and letting go of the interrupt line.
To maintain backwards compatibility, I added a new request for the pulling
part. The letting go part was implemented earlier already.
With this in place, we can now finally start guests that do not randomly stall
and stop to work at random times.
This patch implements above logic for Book3S.
Signed-off-by: Alexander Graf <agraf@suse.de>
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When we're on a paired single capable host, we can just always enable
paired singles and expose them to the guest directly.
This approach breaks when multiple VMs run and access PS concurrently,
but this should suffice until we get a proper framework for it in Linux.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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The Gekko implements an extension called paired singles. When the guest wants
to use that extension, we need to make sure we're not running the host FPU,
because all FPU instructions need to get emulated to accomodate for additional
operations that occur.
This patch adds an hflag to track if we're in paired single mode or not.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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To fetch the last instruction we were interrupted on, we enable DR in early
exit code, where we are still in a very transitional phase between guest
and host state.
Most of the time this seemed to work, but another CPU can easily flush our
TLB and HTAB which makes us go in the Linux page fault handler which totally
breaks because we still use the guest's SLB entries.
To work around that, let's introduce a second KVM guest mode that defines
that whenever we get a trap, we don't call the Linux handler or go into
the KVM exit code, but just jump over the faulting instruction.
That way a potentially bad lwz doesn't trigger any faults and we can later
on interpret the invalid instruction we fetched as "fetch didn't work".
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Currently userspace has no chance to find out which virtual address space we're
in and resolve addresses. While that is a big problem for migration, it's also
unpleasent when debugging, as gdb and the monitor don't work on virtual
addresses.
This patch exports enough of the MMU segment state to userspace to make
debugging work and thus also includes the groundwork for migration.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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We need quite a bunch of new constants for KVM on Book3s,
so let's define them now.
These constants will be used in later patches.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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e500 has additional interrupt vectors (and corresponding IVORs) for SPE and
performance monitoring interrupts.
Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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from include/asm-powerpc. This is the result of a
mkdir arch/powerpc/include/asm
git mv include/asm-powerpc/* arch/powerpc/include/asm
Followed by a few documentation/comment fixups and a couple of places
where <asm-powepc/...> was being used explicitly. Of the latter only
one was outside the arch code and it is a driver only built for powerpc.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Nicholas Piggin
Gustavo Romero
Thomas Gleixner
Paul Mackerras
Suresh Warrier
Mihai Caraman
Linus Torvalds
Mahesh Salgaonkar
Alexander Graf
Paul Mackerras
Michael Ellerman
Kumar Gala
Varun Sethi
Scott Wood
Benjamin Herrenschmidt
Hollis Blanchard
Stephen Rothwell