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2022-09-30KVM: PPC: Book3S HV: Implement scheduling wait interval counters in the VPANicholas Piggin1-21/+41
PAPR specifies accumulated virtual processor wait intervals that relate to partition scheduling interval times. Implement these counters in the same way as they are repoted by dtl. Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220908132545.4085849-5-npiggin@gmail.com
2022-09-28KVM: PPC: Book3S HV P9: Restore stolen time logging in dtlNicholas Piggin1-4/+45
Stolen time logging in dtl was removed from the P9 path, so guests had no stolen time accounting. Add it back in a simpler way that still avoids locks and per-core accounting code. Fixes: ecb6a7207f92 ("KVM: PPC: Book3S HV P9: Remove most of the vcore logic") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220908132545.4085849-4-npiggin@gmail.com
2022-09-28KVM: PPC: Book3S HV: Update guest state entry/exit accounting to new APINicholas Piggin1-21/+10
Update the guest state and timing entry/exit accounting to use the new API, which was introduced following issues found[1]. KVM HV does possibly call instrumented code inside the guest context, and it does call srcu inside the guest context which is fragile at best. Switch to the new API, moving the guest context inside the srcu_read_lock/unlock region. [1] https://lore.kernel.org/lkml/20220201132926.3301912-1-mark.rutland@arm.com/ Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220908132545.4085849-3-npiggin@gmail.com
2022-09-28KVM: PPC: Book3S HV P9: Fix irq disabling in tick accountingNicholas Piggin1-2/+2
kvmhv_run_single_vcpu() disables PMIs as well as Linux irqs, however the tick time accounting code enables and disables irqs and not PMIs within this region. By chance this might not actually cause a bug, but it is clearly an incorrect use of the APIs. Fixes: 2251fbe76395e ("KVM: PPC: Book3S HV P9: Improve mtmsrd scheduling by delaying MSR[EE] disable") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220908132545.4085849-2-npiggin@gmail.com
2022-09-28KVM: PPC: Book3S HV P9: Clear vcpu cpu fields before enabling host irqsNicholas Piggin1-3/+3
On guest entry, vcpu->cpu and vcpu->arch.thread_cpu are set after disabling host irqs. On guest exit there is a window whre tick time accounting briefly enables irqs before these fields are cleared. Move them up to ensure they are cleared before host irqs are run. This is possibly not a problem, but is more symmetric and makes the fields less surprising. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220908132545.4085849-1-npiggin@gmail.com
2022-09-28KVM: PPC: Book3S HV: Fix decrementer migrationFabiano Rosas1-2/+16
We used to have a workaround[1] for a hang during migration that was made ineffective when we converted the decrementer expiry to be relative to guest timebase. The point of the workaround was that in the absence of an explicit decrementer expiry value provided by userspace during migration, KVM needs to initialize dec_expires to a value that will result in an expired decrementer after subtracting the current guest timebase. That stops the vcpu from hanging after migration due to a decrementer that's too large. If the dec_expires is now relative to guest timebase, its initialization needs to be guest timebase-relative as well, otherwise we end up with a decrementer expiry that is still larger than the guest timebase. 1- https://git.kernel.org/torvalds/c/5855564c8ab2 Fixes: 3c1a4322bba7 ("KVM: PPC: Book3S HV: Change dec_expires to be relative to guest timebase") Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220816222517.1916391-1-farosas@linux.ibm.com
2022-08-06Merge tag 'powerpc-6.0-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linuxLinus Torvalds1-3/+25
Pull powerpc updates from Michael Ellerman: - Add support for syscall stack randomization - Add support for atomic operations to the 32 & 64-bit BPF JIT - Full support for KASAN on 64-bit Book3E - Add a watchdog driver for the new PowerVM hypervisor watchdog - Add a number of new selftests for the Power10 PMU support - Add a driver for the PowerVM Platform KeyStore - Increase the NMI watchdog timeout during live partition migration, to avoid timeouts due to increased memory access latency - Add support for using the 'linux,pci-domain' device tree property for PCI domain assignment - Many other small features and fixes Thanks to Alexey Kardashevskiy, Andy Shevchenko, Arnd Bergmann, Athira Rajeev, Bagas Sanjaya, Christophe Leroy, Erhard Furtner, Fabiano Rosas, Greg Kroah-Hartman, Greg Kurz, Haowen Bai, Hari Bathini, Jason A. Donenfeld, Jason Wang, Jiang Jian, Joel Stanley, Juerg Haefliger, Kajol Jain, Kees Cook, Laurent Dufour, Madhavan Srinivasan, Masahiro Yamada, Maxime Bizon, Miaoqian Lin, Murilo Opsfelder Araújo, Nathan Lynch, Naveen N. Rao, Nayna Jain, Nicholas Piggin, Ning Qiang, Pali Rohár, Petr Mladek, Rashmica Gupta, Sachin Sant, Scott Cheloha, Segher Boessenkool, Stephen Rothwell, Uwe Kleine-König, Wolfram Sang, Xiu Jianfeng, and Zhouyi Zhou. * tag 'powerpc-6.0-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (191 commits) powerpc/64e: Fix kexec build error EDAC/ppc_4xx: Include required of_irq header directly powerpc/pci: Fix PHB numbering when using opal-phbid powerpc/64: Init jump labels before parse_early_param() selftests/powerpc: Avoid GCC 12 uninitialised variable warning powerpc/cell/axon_msi: Fix refcount leak in setup_msi_msg_address powerpc/xive: Fix refcount leak in xive_get_max_prio powerpc/spufs: Fix refcount leak in spufs_init_isolated_loader powerpc/perf: Include caps feature for power10 DD1 version powerpc: add support for syscall stack randomization powerpc: Move system_call_exception() to syscall.c powerpc/powernv: rename remaining rng powernv_ functions to pnv_ powerpc/powernv/kvm: Use darn for H_RANDOM on Power9 powerpc/powernv: Avoid crashing if rng is NULL selftests/powerpc: Fix matrix multiply assist test powerpc/signal: Update comment for clarity powerpc: make facility_unavailable_exception 64s powerpc/platforms/83xx/suspend: Remove write-only global variable powerpc/platforms/83xx/suspend: Prevent unloading the driver powerpc/platforms/83xx/suspend: Reorder to get rid of a forward declaration ...
2022-07-25random: handle archrandom with multiple longsJason A. Donenfeld1-1/+1
The archrandom interface was originally designed for x86, which supplies RDRAND/RDSEED for receiving random words into registers, resulting in one function to generate an int and another to generate a long. However, other architectures don't follow this. On arm64, the SMCCC TRNG interface can return between one and three longs. On s390, the CPACF TRNG interface can return arbitrary amounts, with four longs having the same cost as one. On UML, the os_getrandom() interface can return arbitrary amounts. So change the api signature to take a "max_longs" parameter designating the maximum number of longs requested, and then return the number of longs generated. Since callers need to check this return value and loop anyway, each arch implementation does not bother implementing its own loop to try again to fill the maximum number of longs. Additionally, all existing callers pass in a constant max_longs parameter. Taken together, these two things mean that the codegen doesn't really change much for one-word-at-a-time platforms, while performance is greatly improved on platforms such as s390. Acked-by: Heiko Carstens <hca@linux.ibm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Acked-by: Borislav Petkov <bp@suse.de> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-07-25powerpc: Fix all occurences of duplicate wordsMichael Ellerman1-1/+1
Since commit 87c78b612f4f ("powerpc: Fix all occurences of "the the"") fixed "the the", there's now a steady stream of patches fixing other duplicate words. Just fix them all at once, to save the overhead of dealing with individual patches for each case. This leaves a few cases of "that that", which in some contexts is correct. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220718095158.326606-1-mpe@ellerman.id.au
2022-06-29KVM: PPC: Book3S HV: Provide more detailed timings for P9 entry pathFabiano Rosas1-5/+18
Alter the data collection points for the debug timing code in the P9 path to be more in line with what the code does. The points where we accumulate time are now the following: vcpu_entry: From vcpu_run_hv entry until the start of the inner loop; guest_entry: From the start of the inner loop until the guest entry in asm; in_guest: From the guest entry in asm until the return to KVM C code; guest_exit: From the return into KVM C code until the corresponding hypercall/page fault handling or re-entry into the guest; hypercall: Time spent handling hcalls in the kernel (hcalls can go to QEMU, not accounted here); page_fault: Time spent handling page faults; vcpu_exit: vcpu_run_hv exit (almost no code here currently). Like before, these are exposed in debugfs in a file called "timings". There are four values: - number of occurrences of the accumulation point; - total time the vcpu spent in the phase in ns; - shortest time the vcpu spent in the phase in ns; - longest time the vcpu spent in the phase in ns; === Before: rm_entry: 53132 16793518 256 4060 rm_intr: 53132 2125914 22 340 rm_exit: 53132 24108344 374 2180 guest: 53132 40980507996 404 9997650 cede: 0 0 0 0 After: vcpu_entry: 34637 7716108 178 4416 guest_entry: 52414 49365608 324 747542 in_guest: 52411 40828715840 258 9997480 guest_exit: 52410 19681717182 826 102496674 vcpu_exit: 34636 1744462 38 182 hypercall: 45712 22878288 38 1307962 page_fault: 992 111104034 568 168688 With just one instruction (hcall): vcpu_entry: 1 942 942 942 guest_entry: 1 4044 4044 4044 in_guest: 1 1540 1540 1540 guest_exit: 1 3542 3542 3542 vcpu_exit: 1 80 80 80 hypercall: 0 0 0 0 page_fault: 0 0 0 0 === Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220525130554.2614394-6-farosas@linux.ibm.com
2022-06-29KVM: PPC: Book3S HV: Decouple the debug timing from the P8 entry pathFabiano Rosas1-2/+11
We are currently doing the timing for debug purposes of the P9 entry path using the accumulators and terminology defined by the old entry path for P8 machines. Not only the "real-mode" and "napping" mentions are out of place for the P9 Radix entry path but also we cannot change them because the timing code is coupled to the structures defined in struct kvm_vcpu_arch. Add a new CONFIG_KVM_BOOK3S_HV_P9_TIMING to enable the timing code for the P9 entry path. For now, just add the new CONFIG and duplicate the structures. A subsequent patch will add the P9 changes. Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220525130554.2614394-4-farosas@linux.ibm.com
2022-05-19Merge branch 'topic/ppc-kvm' into nextMichael Ellerman1-14/+59
Merge our KVM topic branch.
2022-05-19KVM: PPC: Book3S HV: Fix vcore_blocked tracepointFabiano Rosas1-4/+4
We removed most of the vcore logic from the P9 path but there's still a tracepoint that tried to dereference vc->runner. Fixes: ecb6a7207f92 ("KVM: PPC: Book3S HV P9: Remove most of the vcore logic") Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220328215831.320409-1-farosas@linux.ibm.com
2022-05-19KVM: PPC: Book3s: Retire H_PUT_TCE/etc real mode handlersAlexey Kardashevskiy1-0/+6
LoPAPR defines guest visible IOMMU with hypercalls to use it - H_PUT_TCE/etc. Implemented first on POWER7 where hypercalls would trap in the KVM in the real mode (with MMU off). The problem with the real mode is some memory is not available and some API usage crashed the host but enabling MMU was an expensive operation. The problems with the real mode handlers are: 1. Occasionally these cannot complete the request so the code is copied+modified to work in the virtual mode, very little is shared; 2. The real mode handlers have to be linked into vmlinux to work; 3. An exception in real mode immediately reboots the machine. If the small DMA window is used, the real mode handlers bring better performance. However since POWER8, there has always been a bigger DMA window which VMs use to map the entire VM memory to avoid calling H_PUT_TCE. Such 1:1 mapping happens once and uses H_PUT_TCE_INDIRECT (a bulk version of H_PUT_TCE) which virtual mode handler is even closer to its real mode version. On POWER9 hypercalls trap straight to the virtual mode so the real mode handlers never execute on POWER9 and later CPUs. So with the current use of the DMA windows and MMU improvements in POWER9 and later, there is no point in duplicating the code. The 32bit passed through devices may slow down but we do not have many of these in practice. For example, with this applied, a 1Gbit ethernet adapter still demostrates above 800Mbit/s of actual throughput. This removes the real mode handlers from KVM and related code from the powernv platform. This updates the list of implemented hcalls in KVM-HV as the realmode handlers are removed. This changes ABI - kvmppc_h_get_tce() moves to the KVM module and kvmppc_find_table() is static now. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220506053755.3820702-1-aik@ozlabs.ru
2022-05-19KVM: PPC: Book3S HV: Initialize AMOR in nested entryFabiano Rosas1-0/+1
The hypervisor always sets AMOR to ~0, but let's ensure we're not passing stale values around. Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220425142151.1495142-1-farosas@linux.ibm.com
2022-05-13KVM: PPC: Book3S HV Nested: L2 LPCR should inherit L1 LPES settingNicholas Piggin1-0/+4
The L1 should not be able to adjust LPES mode for the L2. Setting LPES if the L0 needs it clear would cause external interrupts to be sent to L2 and missed by the L0. Clearing LPES when it may be set, as typically happens with XIVE enabled could cause a performance issue despite having no native XIVE support in the guest, because it will cause mediated interrupts for the L2 to be taken in HV mode, which then have to be injected. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220303053315.1056880-7-npiggin@gmail.com
2022-05-13KVM: PPC: Book3S HV Nested: L2 must not run with L1 xive contextNicholas Piggin1-6/+20
The PowerNV L0 currently pushes the OS xive context when running a vCPU, regardless of whether it is running a nested guest. The problem is that xive OS ring interrupts will be delivered while the L2 is running. At the moment, by default, the L2 guest runs with LPCR[LPES]=0, which actually makes external interrupts go to the L0. That causes the L2 to exit and the interrupt taken or injected into the L1, so in some respects this behaves like an escalation. It's not clear if this was deliberate or not, there's no comment about it and the L1 is actually allowed to clear LPES in the L2, so it's confusing at best. When the L2 is running, the L1 is essentially in a ceded state with respect to external interrupts (it can't respond to them directly and won't get scheduled again absent some additional event). So the natural way to solve this is when the L0 handles a H_ENTER_NESTED hypercall to run the L2, have it arm the escalation interrupt and don't push the L1 context while running the L2. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220303053315.1056880-6-npiggin@gmail.com
2022-05-13KVM: PPC: Book3S HV P9: Split !nested case out from guest entryNicholas Piggin1-4/+13
The differences between nested and !nested will become larger in later changes so split them out for readability. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220303053315.1056880-5-npiggin@gmail.com
2022-05-13KVM: PPC: Book3S HV P9: Move cede logic out of XIVE escalation rearmingNicholas Piggin1-2/+8
Move the cede abort logic out of xive escalation rearming and into the caller to prepare for handling a similar case with nested guest entry. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220303053315.1056880-4-npiggin@gmail.com
2022-05-13KVM: PPC: Book3S HV P9: Inject pending xive interrupts at guest entryNicholas Piggin1-2/+7
If there is a pending xive interrupt, inject it at guest entry (if MSR[EE] is enabled) rather than take another interrupt when the guest is entered. If xive is enabled then LPCR[LPES] is set so this behaviour should be expected. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220303053315.1056880-3-npiggin@gmail.com
2022-05-13KVM: PPC: Book3S HV: HFSCR[PREFIX] does not existNicholas Piggin1-1/+1
This facility is controlled by FSCR only. Reserved bits should not be set in the HFSCR register (although it's likely harmless as this position would not be re-used, and the L0 is forgiving here too). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220122105639.3477407-1-npiggin@gmail.com
2022-05-08powerpc: Add missing headersChristophe Leroy1-0/+1
Don't inherit headers "by chances" from asm/prom.h, asm/mpc52xx.h, asm/pci.h etc... Include the needed headers, and remove asm/prom.h when it was needed exclusively for pulling necessary headers. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/be8bdc934d152a7d8ee8d1a840d5596e2f7d85e0.1646767214.git.christophe.leroy@csgroup.eu
2022-03-07KVM: PPC: Book3S HV P9: Fix "lost kick" raceNicholas Piggin1-8/+33
When new work is created that requires attention from the hypervisor (e.g., to inject an interrupt into the guest), fast_vcpu_kick is used to pull the target vcpu out of the guest if it may have been running. Therefore the work creation side looks like this: vcpu->arch.doorbell_request = 1; kvmppc_fast_vcpu_kick_hv(vcpu) { smp_mb(); cpu = vcpu->cpu; if (cpu != -1) send_ipi(cpu); } And the guest entry side *should* look like this: vcpu->cpu = smp_processor_id(); smp_mb(); if (vcpu->arch.doorbell_request) { // do something (abort entry or inject doorbell etc) } But currently the store and load are flipped, so it is possible for the entry to see no doorbell pending, and the doorbell creation misses the store to set cpu, resulting lost work (or at least delayed until the next guest exit). Fix this by reordering the entry operations and adding a smp_mb between them. The P8 path appears to have a similar race which is commented but not addressed yet. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220303053315.1056880-2-npiggin@gmail.com
2022-02-03KVM: PPC: Book3S HV: Free allocated memory if module init failsFabiano Rosas1-4/+11
The module's exit function is not called when the init fails, we need to do cleanup before returning. Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220125155735.1018683-4-farosas@linux.ibm.com
2022-02-03KVM: PPC: Book3S HV: Delay setting of kvm opsFabiano Rosas1-5/+7
Delay the setting of kvm_hv_ops until after all init code has completed. This avoids leaving the ops still accessible if the init fails. Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220125155735.1018683-3-farosas@linux.ibm.com
2022-02-03KVM: PPC: Book3S HV: Check return value of kvmppc_radix_initFabiano Rosas1-1/+4
The return of the function is being shadowed by the call to kvmppc_uvmem_init. Fixes: ca9f4942670c ("KVM: PPC: Book3S HV: Support for running secure guests") Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220125155735.1018683-2-farosas@linux.ibm.com
2022-02-02KVM: PPC: Merge powerpc's debugfs entry content into generic entryAlexey Kardashevskiy1-19/+12
At the moment KVM on PPC creates 4 types of entries under the kvm debugfs: 1) "%pid-%fd" per a KVM instance (for all platforms); 2) "vm%pid" (for PPC Book3s HV KVM); 3) "vm%u_vcpu%u_timing" (for PPC Book3e KVM); 4) "kvm-xive-%p" (for XIVE PPC Book3s KVM, the same for XICS); The problem with this is that multiple VMs per process is not allowed for 2) and 3) which makes it possible for userspace to trigger errors when creating duplicated debugfs entries. This merges all these into 1). This defines kvm_arch_create_kvm_debugfs() similar to kvm_arch_create_vcpu_debugfs(). This defines 2 hooks in kvmppc_ops that allow specific KVM implementations add necessary entries, this adds the _e500 suffix to kvmppc_create_vcpu_debugfs_e500() to make it clear what platform it is for. This makes use of already existing kvm_arch_create_vcpu_debugfs() on PPC. This removes no more used debugfs_dir pointers from PPC kvm_arch structs. This stops removing vcpu entries as once created vcpus stay around for the entire life of a VM and removed when the KVM instance is closed, see commit d56f5136b010 ("KVM: let kvm_destroy_vm_debugfs clean up vCPU debugfs directories"). Suggested-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220111005404.162219-1-aik@ozlabs.ru
2022-01-25KVM: PPC: Book3S HV Nested: Fix nested HFSCR being clobbered with multiple vCPUsNicholas Piggin1-2/+1
The L0 is storing HFSCR requested by the L1 for the L2 in struct kvm_nested_guest when the L1 requests a vCPU enter L2. kvm_nested_guest is not a per-vCPU structure. Hilarity ensues. Fix it by moving the nested hfscr into the vCPU structure together with the other per-vCPU nested fields. Fixes: 8b210a880b35 ("KVM: PPC: Book3S HV Nested: Make nested HFSCR state accessible") Cc: stable@vger.kernel.org # v5.15+ Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220122105530.3477250-1-npiggin@gmail.com
2021-12-19Merge branch 'topic/ppc-kvm' of https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux into HEADPaolo Bonzini1-409/+451
Fix conflicts between memslot overhaul and commit 511d25d6b789f ("KVM: PPC: Book3S: Suppress warnings when allocating too big memory slots") from the powerpc tree.
2021-12-14KVM: PPC: Book3S HV P9: Use kvm_arch_vcpu_get_wait() to get rcuwait objectSean Christopherson1-2/+3
Use kvm_arch_vcpu_get_wait() to get a vCPU's rcuwait object instead of using vcpu->wait directly in kvmhv_run_single_vcpu(). Functionally, this is a nop as vcpu->arch.waitp is guaranteed to point at vcpu->wait. But that is not obvious at first glance, and a future change coming in via the KVM tree, commit 510958e99721 ("KVM: Force PPC to define its own rcuwait object"), will hide vcpu->wait from architectures that define __KVM_HAVE_ARCH_WQP to prevent generic KVM from attepting to wake a vCPU with the wrong rcuwait object. Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211213174556.3871157-1-seanjc@google.com
2021-12-08KVM: Keep memslots in tree-based structures instead of array-based onesMaciej S. Szmigiero1-1/+2
The current memslot code uses a (reverse gfn-ordered) memslot array for keeping track of them. Because the memslot array that is currently in use cannot be modified every memslot management operation (create, delete, move, change flags) has to make a copy of the whole array so it has a scratch copy to work on. Strictly speaking, however, it is only necessary to make copy of the memslot that is being modified, copying all the memslots currently present is just a limitation of the array-based memslot implementation. Two memslot sets, however, are still needed so the VM continues to run on the currently active set while the requested operation is being performed on the second, currently inactive one. In order to have two memslot sets, but only one copy of actual memslots it is necessary to split out the memslot data from the memslot sets. The memslots themselves should be also kept independent of each other so they can be individually added or deleted. These two memslot sets should normally point to the same set of memslots. They can, however, be desynchronized when performing a memslot management operation by replacing the memslot to be modified by its copy. After the operation is complete, both memslot sets once again point to the same, common set of memslot data. This commit implements the aforementioned idea. For tracking of gfns an ordinary rbtree is used since memslots cannot overlap in the guest address space and so this data structure is sufficient for ensuring that lookups are done quickly. The "last used slot" mini-caches (both per-slot set one and per-vCPU one), that keep track of the last found-by-gfn memslot, are still present in the new code. Co-developed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Message-Id: <17c0cf3663b760a0d3753d4ac08c0753e941b811.1638817641.git.maciej.szmigiero@oracle.com>
2021-12-08KVM: PPC: Avoid referencing userspace memory region in memslot updatesSean Christopherson1-9/+3
For PPC HV, get the number of pages directly from the new memslot instead of computing the same from the userspace memory region, and explicitly check for !DELETE instead of inferring the same when toggling mmio_update. The motivation for these changes is to avoid referencing the @mem param so that it can be dropped in a future commit. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Message-Id: <1e97fb5198be25f98ef82e63a8d770c682264cc9.1638817639.git.maciej.szmigiero@oracle.com>
2021-12-08KVM: Let/force architectures to deal with arch specific memslot dataSean Christopherson1-7/+10
Pass the "old" slot to kvm_arch_prepare_memory_region() and force arch code to handle propagating arch specific data from "new" to "old" when necessary. This is a baby step towards dynamically allocating "new" from the get go, and is a (very) minor performance boost on x86 due to not unnecessarily copying arch data. For PPC HV, copy the rmap in the !CREATE and !DELETE paths, i.e. for MOVE and FLAGS_ONLY. This is functionally a nop as the previous behavior would overwrite the pointer for CREATE, and eventually discard/ignore it for DELETE. For x86, copy the arch data only for FLAGS_ONLY changes. Unlike PPC HV, x86 needs to reallocate arch data in the MOVE case as the size of x86's allocations depend on the alignment of the memslot's gfn. Opportunistically tweak kvm_arch_prepare_memory_region()'s param order to match the "commit" prototype. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> [mss: add missing RISCV kvm_arch_prepare_memory_region() change] Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Message-Id: <67dea5f11bbcfd71e3da5986f11e87f5dd4013f9.1638817639.git.maciej.szmigiero@oracle.com>
2021-12-08KVM: Use 'unsigned long' as kvm_for_each_vcpu()'s indexMarc Zyngier1-4/+4
Everywhere we use kvm_for_each_vpcu(), we use an int as the vcpu index. Unfortunately, we're about to move rework the iterator, which requires this to be upgrade to an unsigned long. Let's bite the bullet and repaint all of it in one go. Signed-off-by: Marc Zyngier <maz@kernel.org> Message-Id: <20211116160403.4074052-7-maz@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-02KVM: PPC: Book3S: Suppress warnings when allocating too big memory slotsAlexey Kardashevskiy1-2/+6
The userspace can trigger "vmalloc size %lu allocation failure: exceeds total pages" via the KVM_SET_USER_MEMORY_REGION ioctl. This silences the warning by checking the limit before calling vzalloc() and returns ENOMEM if failed. This does not call underlying valloc helpers as __vmalloc_node() is only exported when CONFIG_TEST_VMALLOC_MODULE and __vmalloc_node_range() is not exported at all. Spotted by syzkaller. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> [mpe: Use 'size' for the variable rather than 'cb'] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210901084512.1658628-1-aik@ozlabs.ru
2021-11-24KVM: PPC: Book3S HV P9: Remove subcore HMI handlingNicholas Piggin1-7/+5
On POWER9 and newer, rather than the complex HMI synchronisation and subcore state, have each thread un-apply the guest TB offset before calling into the early HMI handler. This allows the subcore state to be avoided, including subcore enter / exit guest, which includes an expensive divide that shows up slightly in profiles. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-54-npiggin@gmail.com
2021-11-24KVM: PPC: Book3S HV P9: Stop using vc->dpdesNicholas Piggin1-8/+10
The P9 path uses vc->dpdes only for msgsndp / SMT emulation. This adds an ordering requirement between vcpu->doorbell_request and vc->dpdes for no real benefit. Use vcpu->doorbell_request directly. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-53-npiggin@gmail.com
2021-11-24KVM: PPC: Book3S HV P9: Tidy kvmppc_create_dtl_entryNicholas Piggin1-25/+35
This goes further to removing vcores from the P9 path. Also avoid the memset in favour of explicitly initialising all fields. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-52-npiggin@gmail.com
2021-11-24KVM: PPC: Book3S HV P9: Remove most of the vcore logicNicholas Piggin1-62/+85
The P9 path always uses one vcpu per vcore, so none of the vcore, locks, stolen time, blocking logic, shared waitq, etc., is required. Remove most of it. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-51-npiggin@gmail.com
2021-11-24KVM: PPC: Book3S HV P9: Avoid cpu_in_guest atomics on entry and exitNicholas Piggin1-17/+22
cpu_in_guest is set to determine if a CPU needs to be IPI'ed to exit the guest and notice the need_tlb_flush bit. This can be implemented as a global per-CPU pointer to the currently running guest instead of per-guest cpumasks, saving 2 atomics per entry/exit. P7/8 doesn't require cpu_in_guest, nor does a nested HV (only the L0 does), so move it to the P9 HV path. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-50-npiggin@gmail.com
2021-11-24KVM: PPC: Book3S HV P9: Add unlikely annotation for !mmu_readyNicholas Piggin1-1/+1
The mmu will almost always be ready. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-49-npiggin@gmail.com
2021-11-24KVM: PPC: Book3S HV P9: Improve mfmsr performance on entryNicholas Piggin1-15/+3
Rearrange the MSR saving on entry so it does not follow the mtmsrd to disable interrupts, avoiding a possible RAW scoreboard stall. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-46-npiggin@gmail.com
2021-11-24KVM: PPC: Book3S HV Nested: Avoid extra mftb() in nested entryNicholas Piggin1-0/+12
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
2021-11-24KVM: PPC: Book3S HV P9: Avoid tlbsync sequence on radix guest exitNicholas Piggin1-10/+38
Use the existing TLB flushing logic to IPI the previous CPU and run the necessary barriers before running a guest vCPU on a new physical CPU, to do the necessary radix GTSE barriers for handling the case of an interrupted guest tlbie sequence. This requires the vCPU TLB flush sequence that is currently just done on one thread, to be expanded to ensure the other threads execute a ptesync, because causing them to exit the guest will no longer cause a ptesync by itself. This results in more IPIs than the TLB flush logic requires, but it's a significant win for common case scheduling when the vCPU remains on the same physical CPU. This saves about 520 cycles (nearly 10%) on a guest entry+exit micro benchmark on a POWER9. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-44-npiggin@gmail.com
2021-11-24KVM: PPC: Book3S HV P9: Don't restore PSSCR if not neededNicholas Piggin1-2/+5
This also moves the PSSCR update in nested entry to avoid a SPR scoreboard stall. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-42-npiggin@gmail.com
2021-11-24KVM: PPC: Book3S HV P9: Use Linux SPR save/restore to manage some host SPRsNicholas Piggin1-20/+1
Linux implements SPR save/restore including storage space for registers in the task struct for process context switching. Make use of this similarly to the way we make use of the context switching fp/vec save restore. This improves code reuse, allows some stack space to be saved, and helps with avoiding VRSAVE updates if they are not required. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-39-npiggin@gmail.com
2021-11-24KVM: PPC: Book3S HV P9: Demand fault TM facility registersNicholas Piggin1-6/+20
Use HFSCR facility disabling to implement demand faulting for TM, with a hysteresis counter similar to the load_fp etc counters in context switching that implement the equivalent demand faulting for userspace facilities. This speeds up guest entry/exit by avoiding the register save/restore when a guest is not frequently using them. When a guest does use them often, there will be some additional demand fault overhead, but these are not commonly used facilities. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-38-npiggin@gmail.com
2021-11-24KVM: PPC: Book3S HV P9: Demand fault EBB facility registersNicholas Piggin1-2/+14
Use HFSCR facility disabling to implement demand faulting for EBB, with a hysteresis counter similar to the load_fp etc counters in context switching that implement the equivalent demand faulting for userspace facilities. This speeds up guest entry/exit by avoiding the register save/restore when a guest is not frequently using them. When a guest does use them often, there will be some additional demand fault overhead, but these are not commonly used facilities. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-37-npiggin@gmail.com
2021-11-24KVM: PPC: Book3S HV P9: Restrict DSISR canary workaround to processors that require itNicholas Piggin1-1/+2
Use CPU_FTR_P9_RADIX_PREFETCH_BUG to apply the workaround, to test for DD2.1 and below processors. This saves a mtSPR in guest entry. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-35-npiggin@gmail.com
2021-11-24KVM: PPC: Book3S HV P9: Switch PMU to guest as late as possibleNicholas Piggin1-4/+2
This moves PMU switch to guest as late as possible in entry, and switch back to host as early as possible at exit. This helps the host get the most perf coverage of KVM entry/exit code as possible. This is slightly suboptimal for SPR scheduling point of view when the PMU is enabled, but when perf is disabled there is no real difference. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211123095231.1036501-34-npiggin@gmail.com
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