- 16 Aug, 2021 2 commits
-
-
Maxim Levitsky authored
If L1 disables VMLOAD/VMSAVE intercepts, and doesn't enable Virtual VMLOAD/VMSAVE (currently not supported for the nested hypervisor), then VMLOAD/VMSAVE must operate on the L1 physical memory, which is only possible by making L0 intercept these instructions. Failure to do so allowed the nested guest to run VMLOAD/VMSAVE unintercepted, and thus read/write portions of the host physical memory. Fixes: 89c8a498 ("KVM: SVM: Enable Virtual VMLOAD VMSAVE feature") Suggested-by:
Paolo Bonzini <pbonzini@redhat.com> Signed-off-by:
Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by:
-
Maxim Levitsky authored
* Invert the mask of bits that we pick from L2 in nested_vmcb02_prepare_control * Invert and explicitly use VIRQ related bits bitmask in svm_clear_vintr This fixes a security issue that allowed a malicious L1 to run L2 with AVIC enabled, which allowed the L2 to exploit the uninitialized and enabled AVIC to read/write the host physical memory at some offsets. Fixes: 3d6368ef ("KVM: SVM: Add VMRUN handler") Signed-off-by:
-
- 13 Aug, 2021 10 commits
-
-
Paolo Bonzini authored
Merge topic branch with fixes for both 5.14-rc6 and 5.15.
-
Sean Christopherson authored
Add yet another spinlock for the TDP MMU and take it when marking indirect shadow pages unsync. When using the TDP MMU and L1 is running L2(s) with nested TDP, KVM may encounter shadow pages for the TDP entries managed by L1 (controlling L2) when handling a TDP MMU page fault. The unsync logic is not thread safe, e.g. the kvm_mmu_page fields are not atomic, and misbehaves when a shadow page is marked unsync via a TDP MMU page fault, which runs with mmu_lock held for read, not write. Lack of a critical section manifests most visibly as an underflow of unsync_children in clear_unsync_child_bit() due to unsync_children being corrupted when multiple CPUs write it without a critical section and without atomic operations. But underflow is the best case scenario. The worst case scenario is that unsync_children prematurely hits '0' and leads to guest memory corruption due to KVM neglecting to properly sync shadow pages. Use an entirely new spinlock even though piggybacking tdp_mmu_pages_lock would functionally be ok. Usurping the lock could degrade performance when building upper level page tables on different vCPUs, especially since the unsync flow could hold the lock for a comparatively long time depending on the number of indirect shadow pages and the depth of the paging tree. For simplicity, take the lock for all MMUs, even though KVM could fairly easily know that mmu_lock is held for write. If mmu_lock is held for write, there cannot be contention for the inner spinlock, and marking shadow pages unsync across multiple vCPUs will be slow enough that bouncing the kvm_arch cacheline should be in the noise. Note, even though L2 could theoretically be given access to its own EPT entries, a nested MMU must hold mmu_lock for write and thus cannot race against a TDP MMU page fault. I.e. the additional spinlock only _needs_ to be taken by the TDP MMU, as opposed to being taken by any MMU for a VM that is running with the TDP MMU enabled. Holding mmu_lock for read also prevents the indirect shadow page from being freed. But as above, keep it simple and always take the lock. Alternative #1, the TDP MMU could simply pass "false" for can_unsync and effectively disable unsync behavior for nested TDP. Write protecting leaf shadow pages is unlikely to noticeably impact traditional L1 VMMs, as such VMMs typically don't modify TDP entries, but the same may not hold true for non-standard use cases and/or VMMs that are migrating physical pages (from L1's perspective). Alternative #2, the unsync logic could be made thread safe. In theory, simply converting all relevant kvm_mmu_page fields to atomics and using atomic bitops for the bitmap would suffice. However, (a) an in-depth audit would be required, (b) the code churn would be substantial, and (c) legacy shadow paging would incur additional atomic operations in performance sensitive paths for no benefit (to legacy shadow paging). Fixes: a2855afc ("KVM: x86/mmu: Allow parallel page faults for the TDP MMU") Cc: stable@vger.kernel.org Cc: Ben Gardon <bgardon@google.com> Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <20210812181815.3378104-1-seanjc@google.com> Signed-off-by:
-
Sean Christopherson authored
Set the min_level for the TDP iterator at the root level when zapping all SPTEs to optimize the iterator's try_step_down(). Zapping a non-leaf SPTE will recursively zap all its children, thus there is no need for the iterator to attempt to step down. This avoids rereading the top-level SPTEs after they are zapped by causing try_step_down() to short-circuit. In most cases, optimizing try_step_down() will be in the noise as the cost of zapping SPTEs completely dominates the overall time. The optimization is however helpful if the zap occurs with relatively few SPTEs, e.g. if KVM is zapping in response to multiple memslot updates when userspace is adding and removing read-only memslots for option ROMs. In that case, the task doing the zapping likely isn't a vCPU thread, but it still holds mmu_lock for read and thus can be a noisy neighbor of sorts. Reviewed-by:
Ben Gardon <bgardon@google.com> Signed-off-by:
-
Sean Christopherson authored
Pass "all ones" as the end GFN to signal "zap all" for the TDP MMU and really zap all SPTEs in this case. As is, zap_gfn_range() skips non-leaf SPTEs whose range exceeds the range to be zapped. If shadow_phys_bits is not aligned to the range size of top-level SPTEs, e.g. 512gb with 4-level paging, the "zap all" flows will skip top-level SPTEs whose range extends beyond shadow_phys_bits and leak their SPs when the VM is destroyed. Use the current upper bound (based on host.MAXPHYADDR) to detect that the caller wants to zap all SPTEs, e.g. instead of using the max theoretical gfn, 1 << (52 - 12). The more precise upper bound allows the TDP iterator to terminate its walk earlier when running on hosts with MAXPHYADDR < 52. Add a WARN on kmv->arch.tdp_mmu_pages when the TDP MMU is destroyed to help future debuggers should KVM decide to leak SPTEs again. The bug is most easily reproduced by running (and unloading!) KVM in a VM whose host.MAXPHYADDR < 39, as the SPTE for gfn=0 will be skipped. ============================================================================= BUG kvm_mmu_page_header (Not tainted): Objects remaining in kvm_mmu_page_header on __kmem_cache_shutdown() ----------------------------------------------------------------------------- Slab 0x000000004d8f7af1 objects=22 used=2 fp=0x00000000624d29ac flags=0x4000000000000200(slab|zone=1) CPU: 0 PID: 1582 Comm: rmmod Not tainted 5.14.0-rc2+ #420 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: dump_stack_lvl+0x45/0x59 slab_err+0x95/0xc9 __kmem_cache_shutdown.cold+0x3c/0x158 kmem_cache_destroy+0x3d/0xf0 kvm_mmu_module_exit+0xa/0x30 [kvm] kvm_arch_exit+0x5d/0x90 [kvm] kvm_exit+0x78/0x90 [kvm] vmx_exit+0x1a/0x50 [kvm_intel] __x64_sys_delete_module+0x13f/0x220 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae Fixes: faaf05b0 ("kvm: x86/mmu: Support zapping SPTEs in the TDP MMU") Cc: stable@vger.kernel.org Cc: Ben Gardon <bgardon@google.com> Signed-off-by:
-
Paolo Bonzini authored
Merge tag 'kvmarm-fixes-5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 fixes for 5.14, take #2 - Plug race between enabling MTE and creating vcpus - Fix off-by-one bug when checking whether an address range is RAM
-
Sean Christopherson authored
Use vmx_need_pf_intercept() when determining if L0 wants to handle a #PF in L2 or if the VM-Exit should be forwarded to L1. The current logic fails to account for the case where #PF is intercepted to handle guest.MAXPHYADDR < host.MAXPHYADDR and ends up reflecting all #PFs into L1. At best, L1 will complain and inject the #PF back into L2. At worst, L1 will eat the unexpected fault and cause L2 to hang on infinite page faults. Note, while the bug was technically introduced by the commit that added support for the MAXPHYADDR madness, the shame is all on commit a0c13434 ("KVM: VMX: introduce vmx_need_pf_intercept"). Fixes: 1dbf5d68 ("KVM: VMX: Add guest physical address check in EPT violation and misconfig") Cc: stable@vger.kernel.org Cc: Peter Shier <pshier@google.com> Cc: Oliver Upton <oupton@google.com> Cc: Jim Mattson <jmattson@google.com> Signed-off-by:
-
Junaid Shahid authored
When a nested EPT violation/misconfig is injected into the guest, the shadow EPT PTEs associated with that address need to be synced. This is done by kvm_inject_emulated_page_fault() before it calls nested_ept_inject_page_fault(). However, that will only sync the shadow EPT PTE associated with the current L1 EPTP. Since the ASID is based on EP4TA rather than the full EPTP, so syncing the current EPTP is not enough. The SPTEs associated with any other L1 EPTPs in the prev_roots cache with the same EP4TA also need to be synced. Signed-off-by:
Junaid Shahid <junaids@google.com> Message-Id: <20210806222229.1645356-1-junaids@google.com> Signed-off-by:
-
Paolo Bonzini authored
Merge common topic branch for 5.14-rc6 and 5.15 merge window.
-
Paolo Bonzini authored
hv_vcpu is initialized again a dozen lines below, and at this point vcpu->arch.hyperv is not valid. Remove the initializer. Reported-by:
kernel test robot <lkp@intel.com> Reviewed-by:
-
Sean Christopherson authored
Remove an ancient restriction that disallowed exposing EFER.NX to the guest if EFER.NX=0 on the host, even if NX is fully supported by the CPU. The motivation of the check, added by commit 2cc51560 ("KVM: VMX: Avoid saving and restoring msr_efer on lightweight vmexit"), was to rule out the case of host.EFER.NX=0 and guest.EFER.NX=1 so that KVM could run the guest with the host's EFER.NX and thus avoid context switching EFER if the only divergence was the NX bit. Fast forward to today, and KVM has long since stopped running the guest with the host's EFER.NX. Not only does KVM context switch EFER if host.EFER.NX=1 && guest.EFER.NX=0, KVM also forces host.EFER.NX=0 && guest.EFER.NX=1 when using shadow paging (to emulate SMEP). Furthermore, the entire motivation for the restriction was made obsolete over a decade ago when Intel added dedicated host and guest EFER fields in the VMCS (Nehalem timeframe), which reduced the overhead of context switching EFER from 400+ cycles (2 * WRMSR + 1 * RDMSR) to a mere ~2 cycles. In practice, the removed restriction only affects non-PAE 32-bit kernels, as EFER.NX is set during boot if NX is supported and the kernel will use PAE paging (32-bit or 64-bit), regardless of whether or not the kernel will actually use NX itself (mark PTEs non-executable). Alternatively and/or complementarily, startup_32_smp() in head_32.S could be modified to set EFER.NX=1 regardless of paging mode, thus eliminating the scenario where NX is supported but not enabled. However, that runs the risk of breaking non-KVM non-PAE kernels (though the risk is very, very low as there are no known EFER.NX errata), and also eliminates an easy-to-use mechanism for stressing KVM's handling of guest vs. host EFER across nested virtualization transitions. Suggested-by:
-
- 10 Aug, 2021 1 commit
-
-
Sean Christopherson authored
Use the secondary_exec_controls_get() accessor in vmx_has_waitpkg() to effectively get the controls for the current VMCS, as opposed to using vmx->secondary_exec_controls, which is the cached value of KVM's desired controls for vmcs01 and truly not reflective of any particular VMCS. While the waitpkg control is not dynamic, i.e. vmcs01 will always hold the same waitpkg configuration as vmx->secondary_exec_controls, the same does not hold true for vmcs02 if the L1 VMM hides the feature from L2. If L1 hides the feature _and_ does not intercept MSR_IA32_UMWAIT_CONTROL, L2 could incorrectly read/write L1's virtual MSR instead of taking a #GP. Fixes: 6e3ba4ab ("KVM: vmx: Emulate MSR IA32_UMWAIT_CONTROL") Cc: stable@vger.kernel.org Signed-off-by:
-
- 05 Aug, 2021 1 commit
-
-
Sean Christopherson authored
Take a signed 'long' instead of an 'unsigned long' for the number of pages to add/subtract to the total number of pages used by the MMU. This fixes a zero-extension bug on 32-bit kernels that effectively corrupts the per-cpu counter used by the shrinker. Per-cpu counters take a signed 64-bit value on both 32-bit and 64-bit kernels, whereas kvm_mod_used_mmu_pages() takes an unsigned long and thus an unsigned 32-bit value on 32-bit kernels. As a result, the value used to adjust the per-cpu counter is zero-extended (unsigned -> signed), not sign-extended (signed -> signed), and so KVM's intended -1 gets morphed to 4294967295 and effectively corrupts the counter. This was found by a staggering amount of sheer dumb luck when running kvm-unit-tests on a 32-bit KVM build. The shrinker just happened to kick in while running tests and do_shrink_slab() logged an error about trying to free a negative number of objects. The truly lucky part is that the kernel just happened to be a slightly stale build, as the shrinker no longer yells about negative objects as of commit 18bb473e ("mm: vmscan: shrink deferred objects proportional to priority"). vmscan: shrink_slab: mmu_shrink_scan+0x0/0x210 [kvm] negative objects to delete nr=-858993460 Fixes: bc8a3d89 ("kvm: mmu: Fix overflow on kvm mmu page limit calculation") Cc: stable@vger.kernel.org Cc: Ben Gardon <bgardon@google.com> Signed-off-by:
Jim Mattson <jmattson@google.com> Signed-off-by:
-
- 04 Aug, 2021 4 commits
-
-
Maxim Levitsky authored
The test was mistakenly using addr_gpa2hva on a gva and that happened to work accidentally. Commit 106a2e76 ("KVM: selftests: Lower the min virtual address for misc page allocations") revealed this bug. Fixes: 2c7f76b4 ("selftests: kvm: Add basic Hyper-V clocksources tests", 2021-03-18) Signed-off-by:
-
Mingwei Zhang authored
KVM SEV code uses bitmaps to manage ASID states. ASID 0 was always skipped because it is never used by VM. Thus, in existing code, ASID value and its bitmap postion always has an 'offset-by-1' relationship. Both SEV and SEV-ES shares the ASID space, thus KVM uses a dynamic range [min_asid, max_asid] to handle SEV and SEV-ES ASIDs separately. Existing code mixes the usage of ASID value and its bitmap position by using the same variable called 'min_asid'. Fix the min_asid usage: ensure that its usage is consistent with its name; allocate extra size for ASID 0 to ensure that each ASID has the same value with its bitmap position. Add comments on ASID bitmap allocation to clarify the size change. Signed-off-by:
Mingwei Zhang <mizhang@google.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Marc Orr <marcorr@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Alper Gun <alpergun@google.com> Cc: Dionna Glaze <dionnaglaze@google.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Vipin Sharma <vipinsh@google.com> Cc: Peter Gonda <pgonda@google.com> Cc: Joerg Roedel <joro@8bytes.org> Message-Id: <20210802180903.159381-1-mizhang@google.com> [Fix up sev_asid_free to also index by ASID, as suggested by Sean Christopherson, and use nr_asids in sev_cpu_init. - Paolo] Signed-off-by:
-
Sean Christopherson authored
Use the raw ASID, not ASID-1, when nullifying the last used VMCB when freeing an SEV ASID. The consumer, pre_sev_run(), indexes the array by the raw ASID, thus KVM could get a false negative when checking for a different VMCB if KVM manages to reallocate the same ASID+VMCB combo for a new VM. Note, this cannot cause a functional issue _in the current code_, as pre_sev_run() also checks which pCPU last did VMRUN for the vCPU, and last_vmentry_cpu is initialized to -1 during vCPU creation, i.e. is guaranteed to mismatch on the first VMRUN. However, prior to commit 8a14fe4f ("kvm: x86: Move last_cpu into kvm_vcpu_arch as last_vmentry_cpu"), SVM tracked pCPU on its own and zero-initialized the last_cpu variable. Thus it's theoretically possible that older versions of KVM could miss a TLB flush if the first VMRUN is on pCPU0 and the ASID and VMCB exactly match those of a prior VM. Fixes: 70cd94e6 ("KVM: SVM: VMRUN should use associated ASID when SEV is enabled") Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: stable@vger.kernel.org Signed-off-by:
-
Paolo Bonzini authored
KVM creates a debugfs directory for each VM in order to store statistics about the virtual machine. The directory name is built from the process pid and a VM fd. While generally unique, it is possible to keep a file descriptor alive in a way that causes duplicate directories, which manifests as these messages: [ 471.846235] debugfs: Directory '20245-4' with parent 'kvm' already present! Even though this should not happen in practice, it is more or less expected in the case of KVM for testcases that call KVM_CREATE_VM and close the resulting file descriptor repeatedly and in parallel. When this happens, debugfs_create_dir() returns an error but kvm_create_vm_debugfs() goes on to allocate stat data structs which are later leaked. The slow memory leak was spotted by syzkaller, where it caused OOM reports. Since the issue only affects debugfs, do a lookup before calling debugfs_create_dir, so that the message is downgraded and rate-limited. While at it, ensure kvm->debugfs_dentry is NULL rather than an error if it is not created. This fixes kvm_destroy_vm_debugfs, which was not checking IS_ERR_OR_NULL correctly. Cc: stable@vger.kernel.org Fixes: 536a6f88 ("KVM: Create debugfs dir and stat files for each VM") Reported-by:
Alexey Kardashevskiy <aik@ozlabs.ru> Suggested-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by:
-
- 03 Aug, 2021 4 commits
-
-
Vitaly Kuznetsov authored
Check that #UD is raised if bit 16 is clear in HYPERV_CPUID_FEATURES.EDX and an 'XMM fast' hypercall is issued. Signed-off-by:
Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by:
Siddharth Chandrasekaran <sidcha@amazon.de> Signed-off-by:
-
Vitaly Kuznetsov authored
TLFS states that "Availability of the XMM fast hypercall interface is indicated via the “Hypervisor Feature Identification” CPUID Leaf (0x40000003, see section 2.4.4) ... Any attempt to use this interface when the hypervisor does not indicate availability will result in a #UD fault." Implement the check for 'strict' mode (KVM_CAP_HYPERV_ENFORCE_CPUID). Signed-off-by:
-
Vitaly Kuznetsov authored
Hypercall failures are unusual with potentially far going consequences so it would be useful to see their results when tracing. Signed-off-by:
-
Vitaly Kuznetsov authored
In case guest doesn't have access to the particular hypercall we can avoid reading XMM registers. Signed-off-by:
-
- 30 Jul, 2021 1 commit
-
-
Paolo Bonzini authored
Once an exception has been injected, any side effects related to the exception (such as setting CR2 or DR6) have been taked place. Therefore, once KVM sets the VM-entry interruption information field or the AMD EVENTINJ field, the next VM-entry must deliver that exception. Pending interrupts are processed after injected exceptions, so in theory it would not be a problem to use KVM_INTERRUPT when an injected exception is present. However, DOSEMU is using run->ready_for_interrupt_injection to detect interrupt windows and then using KVM_SET_SREGS/KVM_SET_REGS to inject the interrupt manually. For this to work, the interrupt window must be delayed after the completion of the previous event injection. Cc: stable@vger.kernel.org Reported-by:
Stas Sergeev <stsp2@yandex.ru> Tested-by:
-
- 29 Jul, 2021 2 commits
-
-
Steven Price authored
When enabling KVM_CAP_ARM_MTE the ioctl checks that there are no VCPUs created to ensure that the capability is enabled before the VM is running. However no locks are held at that point so it is (theoretically) possible for another thread in the VMM to create VCPUs between the check and actually setting mte_enabled. Close the race by taking kvm->lock. Reported-by:
Alexandru Elisei <alexandru.elisei@arm.com> Fixes: 673638f4 ("KVM: arm64: Expose KVM_ARM_CAP_MTE") Signed-off-by:
Steven Price <steven.price@arm.com> Signed-off-by:
Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210729160036.20433-1-steven.price@arm.com
-
David Brazdil authored
Hyp checks whether an address range only covers RAM by checking the start/endpoints against a list of memblock_region structs. However, the endpoint here is exclusive but internally is treated as inclusive. Fix the off-by-one error that caused valid address ranges to be rejected. Cc: Quentin Perret <qperret@google.com> Fixes: 90134ac9 ("KVM: arm64: Protect the .hyp sections from the host") Signed-off-by:
David Brazdil <dbrazdil@google.com> Signed-off-by:
-
- 27 Jul, 2021 10 commits
-
-
Paolo Bonzini authored
The arguments to the KVM_CLEAR_DIRTY_LOG ioctl include a pointer, therefore it needs a compat ioctl implementation. Otherwise, 32-bit userspace fails to invoke it on 64-bit kernels; for x86 it might work fine by chance if the padding is zero, but not on big-endian architectures. Reported-by: Thomas Sattler Cc: stable@vger.kernel.org Fixes: 2a31b9db ("kvm: introduce manual dirty log reprotect") Reviewed-by:
Peter Xu <peterx@redhat.com> Signed-off-by:
-
Li RongQing authored
SMT siblings share caches and other hardware, and busy halt polling will degrade its sibling performance if its sibling is working Sean Christopherson suggested as below: "Rather than disallowing halt-polling entirely, on x86 it should be sufficient to simply have the hardware thread yield to its sibling(s) via PAUSE. It probably won't get back all performance, but I would expect it to be close. This compiles on all KVM architectures, and AFAICT the intended usage of cpu_relax() is identical for all architectures." Suggested-by:
Li RongQing <lirongqing@baidu.com> Message-Id: <20210727111247.55510-1-lirongqing@baidu.com> Signed-off-by:
-
Maxim Levitsky authored
Currently when SVM is enabled in guest CPUID, AVIC is inhibited as soon as the guest CPUID is set. AVIC happens to be fully disabled on all vCPUs by the time any guest entry starts (if after migration the entry can be nested). The reason is that currently we disable avic right away on vCPU from which the kvm_request_apicv_update was called and for this case, it happens to be called on all vCPUs (by svm_vcpu_after_set_cpuid). After we stop doing this, AVIC will end up being disabled only when KVM_REQ_APICV_UPDATE is processed which is after we done switching to the nested guest. Fix this by just using vmcb01 in svm_refresh_apicv_exec_ctrl for avic (which is a right thing to do anyway). Signed-off-by:
-
Maxim Levitsky authored
It is possible that AVIC was requested to be disabled but not yet disabled, e.g if the nested entry is done right after svm_vcpu_after_set_cpuid. Signed-off-by:
-
Maxim Levitsky authored
It is possible for AVIC inhibit and AVIC active state to be mismatched. Currently we disable AVIC right away on vCPU which started the AVIC inhibit request thus this warning doesn't trigger but at least in theory, if svm_set_vintr is called at the same time on multiple vCPUs, the warning can happen. Signed-off-by:
-
Christian Borntraeger authored
commit bc9e9e67 ("KVM: debugfs: Reuse binary stats descriptors") did replace the old definitions with the binary ones. While doing that it missed that some files are names different than the counters. This is especially important for kvm_stat which does have special handling for counters named instruction_*. Fixes: commit bc9e9e67 ("KVM: debugfs: Reuse binary stats descriptors") CC: Jing Zhang <jingzhangos@google.com> Signed-off-by:
Christian Borntraeger <borntraeger@de.ibm.com> Message-Id: <20210726150108.5603-1-borntraeger@de.ibm.com> Signed-off-by:
-
Paolo Bonzini authored
Right now, svm_hv_vmcb_dirty_nested_enlightenments has an incorrect dereference of vmcb->control.reserved_sw before the vmcb is checked for being non-NULL. The compiler is usually sinking the dereference after the check; instead of doing this ourselves in the source, ensure that svm_hv_vmcb_dirty_nested_enlightenments is only called with a non-NULL VMCB. Reported-by:
Dan Carpenter <dan.carpenter@oracle.com> Cc: Vineeth Pillai <viremana@linux.microsoft.com> Signed-off-by:
-
David Matlack authored
This test measures the performance effects of KVM's access tracking. Access tracking is driven by the MMU notifiers test_young, clear_young, and clear_flush_young. These notifiers do not have a direct userspace API, however the clear_young notifier can be triggered by marking a pages as idle in /sys/kernel/mm/page_idle/bitmap. This test leverages that mechanism to enable access tracking on guest memory. To measure performance this test runs a VM with a configurable number of vCPUs that each touch every page in disjoint regions of memory. Performance is measured in the time it takes all vCPUs to finish touching their predefined region. Example invocation: $ ./access_tracking_perf_test -v 8 Testing guest mode: PA-bits:ANY, VA-bits:48, 4K pages guest physical test memory offset: 0xffdfffff000 Populating memory : 1.337752570s Writing to populated memory : 0.010177640s Reading from populated memory : 0.009548239s Mark memory idle : 23.973131748s Writing to idle memory : 0.063584496s Mark memory idle : 24.924652964s Reading from idle memory : 0.062042814s Breaking down the results: * "Populating memory": The time it takes for all vCPUs to perform the first write to every page in their region. * "Writing to populated memory" / "Reading from populated memory": The time it takes for all vCPUs to write and read to every page in their region after it has been populated. This serves as a control for the later results. * "Mark memory idle": The time it takes for every vCPU to mark every page in their region as idle through page_idle. * "Writing to idle memory" / "Reading from idle memory": The time it takes for all vCPUs to write and read to every page in their region after it has been marked idle. This test should be portable across architectures but it is only enabled for x86_64 since that's all I have tested. Reviewed-by:
David Matlack <dmatlack@google.com> Message-Id: <20210713220957.3493520-7-dmatlack@google.com> Signed-off-by:
-
David Matlack authored
There is a missing break statement which causes a fallthrough to the next statement where optarg will be null and a segmentation fault will be generated. Fixes: 9e965bb7 ("KVM: selftests: Add backing src parameter to dirty_log_perf_test") Reviewed-by:
-
Juergen Gross authored
KVM_MAX_VCPU_ID is the maximum vcpu-id of a guest, and not the number of vcpu-ids. Fix array indexed by vcpu-id to have KVM_MAX_VCPU_ID+1 elements. Note that this is currently no real problem, as KVM_MAX_VCPU_ID is an odd number, resulting in always enough padding being available at the end of those arrays. Nevertheless this should be fixed in order to avoid rare problems in case someone is using an even number for KVM_MAX_VCPU_ID. Signed-off-by:
Juergen Gross <jgross@suse.com> Message-Id: <20210701154105.23215-2-jgross@suse.com> Cc: stable@vger.kernel.org Signed-off-by:
-
- 26 Jul, 2021 5 commits
-
-
Vitaly Kuznetsov authored
MSR_KVM_ASYNC_PF_ACK MSR is part of interrupt based asynchronous page fault interface and not the original (deprecated) KVM_FEATURE_ASYNC_PF. This is stated in Documentation/virt/kvm/msr.rst. Fixes: 66570e96 ("kvm: x86: only provide PV features if enabled in guest's CPUID") Signed-off-by:
Oliver Upton <oupton@google.com> Message-Id: <20210722123018.260035-1-vkuznets@redhat.com> Signed-off-by:
-
Mauro Carvalho Chehab authored
The conversion tools used during DocBook/LaTeX/html/Markdown->ReST conversion and some cut-and-pasted text contain some characters that aren't easily reachable on standard keyboards and/or could cause troubles when parsed by the documentation build system. Replace the occurences of the following characters: - U+00a0 (' '): NO-BREAK SPACE as it can cause lines being truncated on PDF output Signed-off-by:Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Message-Id: <ff70cb42d63f3a1da66af1b21b8d038418ed5189.1626947264.git.mchehab+huawei@kernel.org> Signed-off-by:
-
Vitaly Kuznetsov authored
'KVM_CAP_ENFORCE_PV_CPUID' doesn't match the define in include/uapi/linux/kvm.h. Signed-off-by:
-
Vitaly Kuznetsov authored
Make svm_copy_vmrun_state()/svm_copy_vmloadsave_state() interface match 'memcpy(dest, src)' to avoid any confusion. No functional change intended. Suggested-by:
-
Vitaly Kuznetsov authored
To match svm_copy_vmrun_state(), rename nested_svm_vmloadsave() to svm_copy_vmloadsave_state(). Opportunistically add missing braces to 'else' branch in vmload_vmsave_interception(). No functional change intended. Suggested-by:
-
