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2021-04-26Merge tag 'docs-5.13' of git://git.lwn.net/linuxLinus Torvalds1-1/+1
Pull documentation updates from Jonathan Corbet: "It's been a relatively busy cycle in docsland, though more than usually well contained to Documentation/ itself. Highlights include: - The Chinese translators have been busy and show no signs of stopping anytime soon. Italian has also caught up. - Aditya Srivastava has been working on improvements to the kernel-doc script. - Thorsten continues his work on reporting-issues.rst and related documentation around regression reporting. - Lots of documentation updates, typo fixes, etc. as usual" * tag 'docs-5.13' of git://git.lwn.net/linux: (139 commits) docs/zh_CN: add openrisc translation to zh_CN index docs/zh_CN: add openrisc index.rst translation docs/zh_CN: add openrisc todo.rst translation docs/zh_CN: add openrisc openrisc_port.rst translation docs/zh_CN: add core api translation to zh_CN index docs/zh_CN: add core-api index.rst translation docs/zh_CN: add core-api irq index.rst translation docs/zh_CN: add core-api irq irqflags-tracing.rst translation docs/zh_CN: add core-api irq irq-domain.rst translation docs/zh_CN: add core-api irq irq-affinity.rst translation docs/zh_CN: add core-api irq concepts.rst translation docs: sphinx-pre-install: don't barf on beta Sphinx releases scripts: kernel-doc: improve parsing for kernel-doc comments syntax docs/zh_CN: two minor fixes in zh_CN/doc-guide/ Documentation: dev-tools: Add Testing Overview docs/zh_CN: add translations in zh_CN/dev-tools/gcov docs: reporting-issues: make people CC the regressions list MAINTAINERS: add regressions mailing list doc:it_IT: align Italian documentation docs/zh_CN: sync reporting-issues.rst ...
2021-04-26KVM: documentation: fix sphinx warningsPaolo Bonzini1-1/+1
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-23Merge tag 'kvmarm-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEADPaolo Bonzini1-1/+23
KVM/arm64 updates for Linux 5.13 New features: - Stage-2 isolation for the host kernel when running in protected mode - Guest SVE support when running in nVHE mode - Force W^X hypervisor mappings in nVHE mode - ITS save/restore for guests using direct injection with GICv4.1 - nVHE panics now produce readable backtraces - Guest support for PTP using the ptp_kvm driver - Performance improvements in the S2 fault handler - Alexandru is now a reviewer (not really a new feature...) Fixes: - Proper emulation of the GICR_TYPER register - Handle the complete set of relocation in the nVHE EL2 object - Get rid of the oprofile dependency in the PMU code (and of the oprofile body parts at the same time) - Debug and SPE fixes - Fix vcpu reset
2021-04-22Merge branch 'kvm-sev-cgroup' into HEADPaolo Bonzini1-2/+105
2021-04-21KVM: x86: Support KVM VMs sharing SEV contextNathan Tempelman1-1/+17
Add a capability for userspace to mirror SEV encryption context from one vm to another. On our side, this is intended to support a Migration Helper vCPU, but it can also be used generically to support other in-guest workloads scheduled by the host. The intention is for the primary guest and the mirror to have nearly identical memslots. The primary benefits of this are that: 1) The VMs do not share KVM contexts (think APIC/MSRs/etc), so they can't accidentally clobber each other. 2) The VMs can have different memory-views, which is necessary for post-copy migration (the migration vCPUs on the target need to read and write to pages, when the primary guest would VMEXIT). This does not change the threat model for AMD SEV. Any memory involved is still owned by the primary guest and its initial state is still attested to through the normal SEV_LAUNCH_* flows. If userspace wanted to circumvent SEV, they could achieve the same effect by simply attaching a vCPU to the primary VM. This patch deliberately leaves userspace in charge of the memslots for the mirror, as it already has the power to mess with them in the primary guest. This patch does not support SEV-ES (much less SNP), as it does not handle handing off attested VMSAs to the mirror. For additional context, we need a Migration Helper because SEV PSP migration is far too slow for our live migration on its own. Using an in-guest migrator lets us speed this up significantly. Signed-off-by: Nathan Tempelman <natet@google.com> Message-Id: <20210408223214.2582277-1-natet@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-20KVM: x86: Add capability to grant VM access to privileged SGX attributeSean Christopherson1-0/+23
Add a capability, KVM_CAP_SGX_ATTRIBUTE, that can be used by userspace to grant a VM access to a priveleged attribute, with args[0] holding a file handle to a valid SGX attribute file. The SGX subsystem restricts access to a subset of enclave attributes to provide additional security for an uncompromised kernel, e.g. to prevent malware from using the PROVISIONKEY to ensure its nodes are running inside a geniune SGX enclave and/or to obtain a stable fingerprint. To prevent userspace from circumventing such restrictions by running an enclave in a VM, KVM restricts guest access to privileged attributes by default. Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Kai Huang <kai.huang@intel.com> Message-Id: <0b099d65e933e068e3ea934b0523bab070cb8cea.1618196135.git.kai.huang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-20doc/virt/kvm: move KVM_CAP_PPC_MULTITCE in section 8Emanuele Giuseppe Esposito1-125/+125
KVM_CAP_PPC_MULTITCE is a capability, not an ioctl. Therefore move it from section 4.97 to the new 8.31 (other capabilities). To fill the gap, move KVM_X86_SET_MSR_FILTER (was 4.126) to 4.97, and shifted Xen-related ioctl (were 4.127 - 4.130) by one place (4.126 - 4.129). Also fixed minor typo in KVM_GET_MSR_INDEX_LIST ioctl description (section 4.3). Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-Id: <20210316170814.64286-1-eesposit@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-17KVM: introduce KVM_CAP_SET_GUEST_DEBUG2Paolo Bonzini1-0/+3
This capability will allow the user to know which KVM_GUESTDBG_* bits are supported. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20210401135451.1004564-3-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-13Merge branch 'kvm-arm64/ptp' into kvmarm-master/nextMarc Zyngier1-0/+10
Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-04-13Merge branch 'kvm-arm64/misc-5.13' into kvmarm-master/nextMarc Zyngier1-0/+12
Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-04-09KVM: arm64: Clarify vcpu reset behaviourMarc Zyngier1-0/+12
Although the KVM_ARM_VCPU_INIT documentation mention that the registers are reset to their "initial values", it doesn't describe what these values are. Describe this state explicitly. Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-04-07Documentation: KVM: Document KVM_GUESTDBG_USE_HW control flag for arm64Alexandru Elisei1-1/+2
Commit 21b6f32f9471 ("KVM: arm64: guest debug, define API headers") added the arm64 KVM_GUESTDBG_USE_HW flag for the KVM_SET_GUEST_DEBUG ioctl and commit 834bf88726f0 ("KVM: arm64: enable KVM_CAP_SET_GUEST_DEBUG") documented and implemented the flag functionality. Since its introduction, at no point was the flag known by any name other than KVM_GUESTDBG_USE_HW for the arm64 architecture, so refer to it as such in the documentation. CC: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210407144857.199746-2-alexandru.elisei@arm.com
2021-04-07KVM: arm64: Add support for the KVM PTP serviceJianyong Wu1-0/+10
Implement the hypervisor side of the KVM PTP interface. The service offers wall time and cycle count from host to guest. The caller must specify whether they want the host's view of either the virtual or physical counter. Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201209060932.212364-7-jianyong.wu@arm.com
2021-03-19documentation/kvm: additional explanations on KVM_SET_BOOT_CPU_IDEmanuele Giuseppe Esposito1-1/+2
The ioctl KVM_SET_BOOT_CPU_ID fails when called after vcpu creation. Add this explanation in the documentation. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-Id: <20210319091650.11967-1-eesposit@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-18KVM: x86: Protect userspace MSR filter with SRCU, and set atomically-ishSean Christopherson1-2/+4
Fix a plethora of issues with MSR filtering by installing the resulting filter as an atomic bundle instead of updating the live filter one range at a time. The KVM_X86_SET_MSR_FILTER ioctl() isn't truly atomic, as the hardware MSR bitmaps won't be updated until the next VM-Enter, but the relevant software struct is atomically updated, which is what KVM really needs. Similar to the approach used for modifying memslots, make arch.msr_filter a SRCU-protected pointer, do all the work configuring the new filter outside of kvm->lock, and then acquire kvm->lock only when the new filter has been vetted and created. That way vCPU readers either see the old filter or the new filter in their entirety, not some half-baked state. Yuan Yao pointed out a use-after-free in ksm_msr_allowed() due to a TOCTOU bug, but that's just the tip of the iceberg... - Nothing is __rcu annotated, making it nigh impossible to audit the code for correctness. - kvm_add_msr_filter() has an unpaired smp_wmb(). Violation of kernel coding style aside, the lack of a smb_rmb() anywhere casts all code into doubt. - kvm_clear_msr_filter() has a double free TOCTOU bug, as it grabs count before taking the lock. - kvm_clear_msr_filter() also has memory leak due to the same TOCTOU bug. The entire approach of updating the live filter is also flawed. While installing a new filter is inherently racy if vCPUs are running, fixing the above issues also makes it trivial to ensure certain behavior is deterministic, e.g. KVM can provide deterministic behavior for MSRs with identical settings in the old and new filters. An atomic update of the filter also prevents KVM from getting into a half-baked state, e.g. if installing a filter fails, the existing approach would leave the filter in a half-baked state, having already committed whatever bits of the filter were already processed. [*] https://lkml.kernel.org/r/20210312083157.25403-1-yaoyuan0329os@gmail.com Fixes: 1a155254ff93 ("KVM: x86: Introduce MSR filtering") Cc: stable@vger.kernel.org Cc: Alexander Graf <graf@amazon.com> Reported-by: Yuan Yao <yaoyuan0329os@gmail.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210316184436.2544875-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-12KVM: arm64: Reject VM creation when the default IPA size is unsupportedMarc Zyngier1-0/+3
KVM/arm64 has forever used a 40bit default IPA space, partially due to its 32bit heritage (where the only choice is 40bit). However, there are implementations in the wild that have a *cough* much smaller *cough* IPA space, which leads to a misprogramming of VTCR_EL2, and a guest that is stuck on its first memory access if userspace dares to ask for the default IPA setting (which most VMMs do). Instead, blundly reject the creation of such VM, as we can't satisfy the requirements from userspace (with a one-off warning). Also clarify the boot warning, and document that the VM creation will fail when an unsupported IPA size is provided. Although this is an ABI change, it doesn't really change much for userspace: - the guest couldn't run before this change, but no error was returned. At least userspace knows what is happening. - a memory slot that was accepted because it did fit the default IPA space now doesn't even get a chance to be registered. The other thing that is left doing is to convince userspace to actually use the IPA space setting instead of relying on the antiquated default. Fixes: 233a7cb23531 ("kvm: arm64: Allow tuning the physical address size for VM") Signed-off-by: Marc Zyngier <maz@kernel.org> Cc: stable@vger.kernel.org Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Link: https://lore.kernel.org/r/20210311100016.3830038-2-maz@kernel.org
2021-03-08docs: kvm: Fix a typo ("althought")Jonathan Neuschäfer1-1/+1
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net> Link: https://lore.kernel.org/r/20210301214722.2310911-1-j.neuschaefer@gmx.net Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-03-02KVM: x86/xen: Add support for vCPU runstate informationDavid Woodhouse1-0/+41
This is how Xen guests do steal time accounting. The hypervisor records the amount of time spent in each of running/runnable/blocked/offline states. In the Xen accounting, a vCPU is still in state RUNSTATE_running while in Xen for a hypercall or I/O trap, etc. Only if Xen explicitly schedules does the state become RUNSTATE_blocked. In KVM this means that even when the vCPU exits the kvm_run loop, the state remains RUNSTATE_running. The VMM can explicitly set the vCPU to RUNSTATE_blocked by using the KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT attribute, and can also use KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST to retrospectively add a given amount of time to the blocked state and subtract it from the running state. The state_entry_time corresponds to get_kvmclock_ns() at the time the vCPU entered the current state, and the total times of all four states should always add up to state_entry_time. Co-developed-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20210301125309.874953-2-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-02KVM: Documentation: Fix index for KVM_CAP_PPC_DAWR1Kai Huang1-1/+1
It should be 7.23 instead of 7.22, which has already been taken by KVM_CAP_X86_BUS_LOCK_EXIT. Signed-off-by: Kai Huang <kai.huang@intel.com> Message-Id: <20210226094832.380394-1-kai.huang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-26KVM: Documentation: rectify rst markup in kvm_run->flagsChenyi Qiang1-1/+2
Commit c32b1b896d2a ("KVM: X86: Add the Document for KVM_CAP_X86_BUS_LOCK_EXIT") added a new flag in kvm_run->flags documentation, and caused warning in make htmldocs: Documentation/virt/kvm/api.rst:5004: WARNING: Unexpected indentation Documentation/virt/kvm/api.rst:5004: WARNING: Inline emphasis start-string without end-string Fix this rst markup issue. Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com> Message-Id: <20210226075541.27179-1-chenyi.qiang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-26Documentation: kvm: fix messy conversion from .txt to .rstPaolo Bonzini1-53/+16
Building the documentation gives a warning that the KVM_PPC_RESIZE_HPT_PREPARE label is defined twice. The root cause is that the KVM_PPC_RESIZE_HPT_PREPARE API is present twice, the second being a mix of the prepare and commit APIs. Fix it. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-22KVM: Documentation: rectify rst markup in KVM_GET_SUPPORTED_HV_CPUIDLukas Bulwahn1-0/+2
Commit c21d54f0307f ("KVM: x86: hyper-v: allow KVM_GET_SUPPORTED_HV_CPUID as a system ioctl") added an enumeration in the KVM_GET_SUPPORTED_HV_CPUID documentation improperly for rst, and caused new warnings in make htmldocs: Documentation/virt/kvm/api.rst:4536: WARNING: Unexpected indentation. Documentation/virt/kvm/api.rst:4538: WARNING: Block quote ends without a blank line; unexpected unindent. Fix that issue and another historic rst markup issue from the initial rst conversion in the KVM_GET_SUPPORTED_HV_CPUID documentation. Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Message-Id: <20210104095938.24838-1-lukas.bulwahn@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-10KVM: PPC: Book3S HV: Introduce new capability for 2nd DAWRRavi Bangoria1-0/+10
Introduce KVM_CAP_PPC_DAWR1 which can be used by QEMU to query whether KVM supports 2nd DAWR or not. The capability is by default disabled even when the underlying CPU supports 2nd DAWR. QEMU needs to check and enable it manually to use the feature. Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2021-02-10KVM: PPC: Book3S HV: Add infrastructure to support 2nd DAWRRavi Bangoria1-0/+2
KVM code assumes single DAWR everywhere. Add code to support 2nd DAWR. DAWR is a hypervisor resource and thus H_SET_MODE hcall is used to set/ unset it. Introduce new case H_SET_MODE_RESOURCE_SET_DAWR1 for 2nd DAWR. Also, KVM will support 2nd DAWR only if CPU_FTR_DAWR1 is set. Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2021-02-09Documentation: kvm: fix warningPaolo Bonzini1-1/+1
Documentation/virt/kvm/api.rst:4927: WARNING: Title underline too short. 4.130 KVM_XEN_VCPU_GET_ATTR -------------------------- Fixes: e1f68169a4f8 ("KVM: Add documentation for Xen hypercall and shared_info updates") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-04KVM: Add documentation for Xen hypercall and shared_info updatesDavid Woodhouse1-5/+166
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
2021-02-04KVM: X86: Add the Document for KVM_CAP_X86_BUS_LOCK_EXITChenyi Qiang1-3/+42
Introduce a new capability named KVM_CAP_X86_BUS_LOCK_EXIT, which is used to handle bus locks detected in guest. It allows the userspace to do custom throttling policies to mitigate the 'noisy neighbour' problem. Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com> Message-Id: <20201106090315.18606-5-chenyi.qiang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-25KVM: Documentation: Update description of KVM_{GET,CLEAR}_DIRTY_LOGZenghui Yu1-9/+7
Update various words, including the wrong parameter name and the vague description of the usage of "slot" field. Signed-off-by: Zenghui Yu <yuzenghui@huawei.com> Message-Id: <20201208043439.895-1-yuzenghui@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-25KVM: Documentation: Fix spec for KVM_CAP_ENABLE_CAP_VMQuentin Perret1-1/+1
The documentation classifies KVM_ENABLE_CAP with KVM_CAP_ENABLE_CAP_VM as a vcpu ioctl, which is incorrect. Fix it by specifying it as a VM ioctl. Fixes: e5d83c74a580 ("kvm: make KVM_CAP_ENABLE_CAP_VM architecture agnostic") Signed-off-by: Quentin Perret <qperret@google.com> Message-Id: <20210108165349.747359-1-qperret@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-25Merge tag 'kvmarm-fixes-5.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEADPaolo Bonzini1-0/+3
KVM/arm64 fixes for 5.11, take #2 - Don't allow tagged pointers to point to memslots - Filter out ARMv8.1+ PMU events on v8.0 hardware - Hide PMU registers from userspace when no PMU is configured - More PMU cleanups - Don't try to handle broken PSCI firmware - More sys_reg() to reg_to_encoding() conversions
2021-01-21KVM: Forbid the use of tagged userspace addresses for memslotsMarc Zyngier1-0/+3
The use of a tagged address could be pretty confusing for the whole memslot infrastructure as well as the MMU notifiers. Forbid it altogether, as it never quite worked the first place. Cc: stable@vger.kernel.org Reported-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-01-08Merge tag 'kvmarm-fixes-5.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEADPaolo Bonzini1-2/+7
KVM/arm64 fixes for 5.11, take #1 - VM init cleanups - PSCI relay cleanups - Kill CONFIG_KVM_ARM_PMU - Fixup __init annotations - Fixup reg_to_encoding() - Fix spurious PMCR_EL0 access
2020-12-23KVM: Documentation: Add arm64 KVM_RUN error codesAlexandru Elisei1-2/+7
The API documentation states that general error codes are not detailed, but errors with specific meanings are. On arm64, KVM_RUN can return error numbers with a different meaning than what is described by POSIX or the C99 standard (as taken from man 3 errno). Absent from the newly documented error codes is ERANGE which can be returned when making a change to the EL2 stage 1 tables if the address is larger than the largest supported input address. Assuming no bugs in the implementation, that is not possible because the input addresses which are mapped are the result of applying the macro kern_hyp_va() on kernel virtual addresses. CC: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201201150157.223625-2-alexandru.elisei@arm.com
2020-11-15KVM: Make dirty ring exclusive to dirty bitmap logPeter Xu1-0/+7
There's no good reason to use both the dirty bitmap logging and the new dirty ring buffer to track dirty bits. We should be able to even support both of them at the same time, but it could complicate things which could actually help little. Let's simply make it the rule before we enable dirty ring on any arch, that we don't allow these two interfaces to be used together. The big world switch would be KVM_CAP_DIRTY_LOG_RING capability enablement. That's where we'll switch from the default dirty logging way to the dirty ring way. As long as kvm->dirty_ring_size is setup correctly, we'll once and for all switch to the dirty ring buffer mode for the current virtual machine. Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20201001012224.5818-1-peterx@redhat.com> [Change errno from EINVAL to ENXIO. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-11-15KVM: X86: Implement ring-based dirty memory trackingPeter Xu1-0/+93
This patch is heavily based on previous work from Lei Cao <lei.cao@stratus.com> and Paolo Bonzini <pbonzini@redhat.com>. [1] KVM currently uses large bitmaps to track dirty memory. These bitmaps are copied to userspace when userspace queries KVM for its dirty page information. The use of bitmaps is mostly sufficient for live migration, as large parts of memory are be dirtied from one log-dirty pass to another. However, in a checkpointing system, the number of dirty pages is small and in fact it is often bounded---the VM is paused when it has dirtied a pre-defined number of pages. Traversing a large, sparsely populated bitmap to find set bits is time-consuming, as is copying the bitmap to user-space. A similar issue will be there for live migration when the guest memory is huge while the page dirty procedure is trivial. In that case for each dirty sync we need to pull the whole dirty bitmap to userspace and analyse every bit even if it's mostly zeros. The preferred data structure for above scenarios is a dense list of guest frame numbers (GFN). This patch series stores the dirty list in kernel memory that can be memory mapped into userspace to allow speedy harvesting. This patch enables dirty ring for X86 only. However it should be easily extended to other archs as well. [1] https://patchwork.kernel.org/patch/10471409/ Signed-off-by: Lei Cao <lei.cao@stratus.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20201001012222.5767-1-peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-11-15KVM: x86: hyper-v: allow KVM_GET_SUPPORTED_HV_CPUID as a system ioctlVitaly Kuznetsov1-5/+11
KVM_GET_SUPPORTED_HV_CPUID is a vCPU ioctl but its output is now independent from vCPU and in some cases VMMs may want to use it as a system ioctl instead. In particular, QEMU doesn CPU feature expansion before any vCPU gets created so KVM_GET_SUPPORTED_HV_CPUID can't be used. Convert KVM_GET_SUPPORTED_HV_CPUID to 'dual' system/vCPU ioctl with the same meaning. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20200929150944.1235688-2-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-11-08KVM: Documentation: Update entry for KVM_CAP_ENFORCE_PV_CPUIDPeter Xu1-2/+1
Should be squashed into 66570e966dd9cb4f. Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20201023183358.50607-3-peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-11-08KVM: Documentation: Update entry for KVM_X86_SET_MSR_FILTERPeter Xu1-1/+1
It should be an accident when rebase, since we've already have section 8.25 (which is KVM_CAP_S390_DIAG318). Fix the number. Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20201001012044.5151-2-peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-23Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds1-9/+207
Pull KVM updates from Paolo Bonzini: "For x86, there is a new alternative and (in the future) more scalable implementation of extended page tables that does not need a reverse map from guest physical addresses to host physical addresses. For now it is disabled by default because it is still lacking a few of the existing MMU's bells and whistles. However it is a very solid piece of work and it is already available for people to hammer on it. Other updates: ARM: - New page table code for both hypervisor and guest stage-2 - Introduction of a new EL2-private host context - Allow EL2 to have its own private per-CPU variables - Support of PMU event filtering - Complete rework of the Spectre mitigation PPC: - Fix for running nested guests with in-kernel IRQ chip - Fix race condition causing occasional host hard lockup - Minor cleanups and bugfixes x86: - allow trapping unknown MSRs to userspace - allow userspace to force #GP on specific MSRs - INVPCID support on AMD - nested AMD cleanup, on demand allocation of nested SVM state - hide PV MSRs and hypercalls for features not enabled in CPUID - new test for MSR_IA32_TSC writes from host and guest - cleanups: MMU, CPUID, shared MSRs - LAPIC latency optimizations ad bugfixes" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (232 commits) kvm: x86/mmu: NX largepage recovery for TDP MMU kvm: x86/mmu: Don't clear write flooding count for direct roots kvm: x86/mmu: Support MMIO in the TDP MMU kvm: x86/mmu: Support write protection for nesting in tdp MMU kvm: x86/mmu: Support disabling dirty logging for the tdp MMU kvm: x86/mmu: Support dirty logging for the TDP MMU kvm: x86/mmu: Support changed pte notifier in tdp MMU kvm: x86/mmu: Add access tracking for tdp_mmu kvm: x86/mmu: Support invalidate range MMU notifier for TDP MMU kvm: x86/mmu: Allocate struct kvm_mmu_pages for all pages in TDP MMU kvm: x86/mmu: Add TDP MMU PF handler kvm: x86/mmu: Remove disallowed_hugepage_adjust shadow_walk_iterator arg kvm: x86/mmu: Support zapping SPTEs in the TDP MMU KVM: Cache as_id in kvm_memory_slot kvm: x86/mmu: Add functions to handle changed TDP SPTEs kvm: x86/mmu: Allocate and free TDP MMU roots kvm: x86/mmu: Init / Uninit the TDP MMU kvm: x86/mmu: Introduce tdp_iter KVM: mmu: extract spte.h and spte.c KVM: mmu: Separate updating a PTE from kvm_set_pte_rmapp ...
2020-10-21kvm: x86: only provide PV features if enabled in guest's CPUIDOliver Upton1-0/+11
KVM unconditionally provides PV features to the guest, regardless of the configured CPUID. An unwitting guest that doesn't check KVM_CPUID_FEATURES before use could access paravirt features that userspace did not intend to provide. Fix this by checking the guest's CPUID before performing any paravirtual operations. Introduce a capability, KVM_CAP_ENFORCE_PV_FEATURE_CPUID, to gate the aforementioned enforcement. Migrating a VM from a host w/o this patch to a host with this patch could silently change the ABI exposed to the guest, warranting that we default to the old behavior and opt-in for the new one. Reviewed-by: Jim Mattson <jmattson@google.com> Reviewed-by: Peter Shier <pshier@google.com> Signed-off-by: Oliver Upton <oupton@google.com> Change-Id: I202a0926f65035b872bfe8ad15307c026de59a98 Message-Id: <20200818152429.1923996-4-oupton@google.com> Reviewed-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: VMX: Forbid userspace MSR filters for x2APICPaolo Bonzini1-8/+10
Allowing userspace to intercept reads to x2APIC MSRs when APICV is fully enabled for the guest simply can't work. But more in general, the LAPIC could be set to in-kernel after the MSR filter is setup and allowing accesses by userspace would be very confusing. We could in principle allow userspace to intercept reads and writes to TPR, and writes to EOI and SELF_IPI, but while that could be made it work, it would still be silly. Cc: Alexander Graf <graf@amazon.com> Cc: Aaron Lewis <aaronlewis@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21KVM: VMX: Ignore userspace MSR filters for x2APICSean Christopherson1-11/+16
Rework the resetting of the MSR bitmap for x2APIC MSRs to ignore userspace filtering. Allowing userspace to intercept reads to x2APIC MSRs when APICV is fully enabled for the guest simply can't work; the LAPIC and thus virtual APIC is in-kernel and cannot be directly accessed by userspace. To keep things simple we will in fact forbid intercepting x2APIC MSRs altogether, independent of the default_allow setting. Cc: Alexander Graf <graf@amazon.com> Cc: Aaron Lewis <aaronlewis@google.com> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20201005195532.8674-3-sean.j.christopherson@intel.com> [Modified to operate even if APICv is disabled, adjust documentation. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-12Merge tag 'docs-5.10' of git://git.lwn.net/linuxLinus Torvalds1-2/+2
Pull documentation updates from Jonathan Corbet: "As hoped, things calmed down for docs this cycle; fewer changes and almost no conflicts at all. This includes: - A reworked and expanded user-mode Linux document - Some simplifications and improvements for submitting-patches.rst - An emergency fix for (some) problems with Sphinx 3.x - Some welcome automarkup improvements to automatically generate cross-references to struct definitions and other documents - The usual collection of translation updates, typo fixes, etc" * tag 'docs-5.10' of git://git.lwn.net/linux: (81 commits) gpiolib: Update indentation in driver.rst for code excerpts Documentation/admin-guide: tainted-kernels: Fix typo occured Documentation: better locations for sysfs-pci, sysfs-tagging docs: programming-languages: refresh blurb on clang support Documentation: kvm: fix a typo Documentation: Chinese translation of Documentation/arm64/amu.rst doc: zh_CN: index files in arm64 subdirectory mailmap: add entry for <mstarovoitov@marvell.com> doc: seq_file: clarify role of *pos in ->next() docs: trace: ring-buffer-design.rst: use the new SPDX tag Documentation: kernel-parameters: clarify "module." parameters Fix references to nommu-mmap.rst docs: rewrite admin-guide/sysctl/abi.rst docs: fb: Remove vesafb scrollback boot option docs: fb: Remove sstfb scrollback boot option docs: fb: Remove matroxfb scrollback boot option docs: fb: Remove framebuffer scrollback boot option docs: replace the old User Mode Linux HowTo with a new one Documentation/admin-guide: blockdev/ramdisk: remove use of "rdev" Documentation/admin-guide: README & svga: remove use of "rdev" ...
2020-09-28KVM: x86: Introduce MSR filteringAlexander Graf1-0/+108
It's not desireable to have all MSRs always handled by KVM kernel space. Some MSRs would be useful to handle in user space to either emulate behavior (like uCode updates) or differentiate whether they are valid based on the CPU model. To allow user space to specify which MSRs it wants to see handled by KVM, this patch introduces a new ioctl to push filter rules with bitmaps into KVM. Based on these bitmaps, KVM can then decide whether to reject MSR access. With the addition of KVM_CAP_X86_USER_SPACE_MSR it can also deflect the denied MSR events to user space to operate on. If no filter is populated, MSR handling stays identical to before. Signed-off-by: Alexander Graf <graf@amazon.com> Message-Id: <20200925143422.21718-8-graf@amazon.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-09-28KVM: x86: Allow deflecting unknown MSR accesses to user spaceAlexander Graf1-8/+77
MSRs are weird. Some of them are normal control registers, such as EFER. Some however are registers that really are model specific, not very interesting to virtualization workloads, and not performance critical. Others again are really just windows into package configuration. Out of these MSRs, only the first category is necessary to implement in kernel space. Rarely accessed MSRs, MSRs that should be fine tunes against certain CPU models and MSRs that contain information on the package level are much better suited for user space to process. However, over time we have accumulated a lot of MSRs that are not the first category, but still handled by in-kernel KVM code. This patch adds a generic interface to handle WRMSR and RDMSR from user space. With this, any future MSR that is part of the latter categories can be handled in user space. Furthermore, it allows us to replace the existing "ignore_msrs" logic with something that applies per-VM rather than on the full system. That way you can run productive VMs in parallel to experimental ones where you don't care about proper MSR handling. Signed-off-by: Alexander Graf <graf@amazon.com> Reviewed-by: Jim Mattson <jmattson@google.com> Message-Id: <20200925143422.21718-3-graf@amazon.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-09-28KVM: x86: hyper-v: Mention SynDBG CPUID leaves in api.rstVitaly Kuznetsov1-1/+4
We forgot to update KVM_GET_SUPPORTED_HV_CPUID's documentation in api.rst when SynDBG leaves were added. While on it, fix 'KVM_GET_SUPPORTED_CPUID' copy-paste error. Fixes: f97f5a56f597 ("x86/kvm/hyper-v: Add support for synthetic debugger interface") Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20200924145757.1035782-2-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-09-14docs: kvm: add documentation for KVM_CAP_S390_DIAG318Collin Walling1-0/+20
Documentation for the s390 DIAGNOSE 0x318 instruction handling. Signed-off-by: Collin Walling <walling@linux.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/kvm/20200625150724.10021-2-walling@linux.ibm.com/ Message-Id: <20200625150724.10021-2-walling@linux.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2020-09-10docs: kvm: api.rst: add missing spacesMauro Carvalho Chehab1-1/+1
There are some warnings: Documentation/virt/kvm/api.rst:4354: WARNING: Definition list ends without a blank line; unexpected unindent. Documentation/virt/kvm/api.rst:4358: WARNING: Definition list ends without a blank line; unexpected unindent. Documentation/virt/kvm/api.rst:4363: WARNING: Definition list ends without a blank line; unexpected unindent. Produced by the lack of identation on a single line. That caused the literal block to end prematurely. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/b6b3679b6c2329dc9b16d397c289b5ade0184c63.1599660067.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-09-09docs: kvm: fix referenced ioctl symbolConnor Kuehl1-1/+1
The actual symbol that is exported and usable is 'KVM_MEMORY_ENCRYPT_OP', not 'KVM_MEM_ENCRYPT_OP' $ git grep -l KVM_MEM_ENCRYPT_OP Documentation/virt/kvm/amd-memory-encryption.rst $ git grep -l KVM_MEMORY_ENCRYPT_OP Documentation/virt/kvm/api.rst arch/x86/kvm/x86.c include/uapi/linux/kvm.h tools/include/uapi/linux/kvm.h While we're in there, update the KVM API category for KVM_MEMORY_ENCRYPT_OP. It is called on a VM file descriptor. Signed-off-by: Connor Kuehl <ckuehl@redhat.com> Link: https://lore.kernel.org/r/20200819211952.251984-1-ckuehl@redhat.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-08-21arm64/x86: KVM: Introduce steal-time capAndrew Jones1-0/+13
arm64 requires a vcpu fd (KVM_HAS_DEVICE_ATTR vcpu ioctl) to probe support for steal-time. However this is unnecessary, as only a KVM fd is required, and it complicates userspace (userspace may prefer delaying vcpu creation until after feature probing). Introduce a cap that can be checked instead. While x86 can already probe steal-time support with a kvm fd (KVM_GET_SUPPORTED_CPUID), we add the cap there too for consistency. Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Steven Price <steven.price@arm.com> Link: https://lore.kernel.org/r/20200804170604.42662-7-drjones@redhat.com