aboutsummaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2019-09-27 12:44:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-27 12:44:26 -0700
commit8bbe0dec38e147a50e9dd5f585295f7e68e0f2d0 (patch)
tree0781fd7dd090bbccd88f1f58caf6387a585b9ebe /Documentation
parente37e3bc7e265d05d00f14079767537699cf6bd46 (diff)
parentfd3edd4a9066f28de99a16685a586d68a9f551f8 (diff)
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull more KVM updates from Paolo Bonzini: "x86 KVM changes: - The usual accuracy improvements for nested virtualization - The usual round of code cleanups from Sean - Added back optimizations that were prematurely removed in 5.2 (the bare minimum needed to fix the regression was in 5.3-rc8, here comes the rest) - Support for UMWAIT/UMONITOR/TPAUSE - Direct L2->L0 TLB flushing when L0 is Hyper-V and L1 is KVM - Tell Windows guests if SMT is disabled on the host - More accurate detection of vmexit cost - Revert a pvqspinlock pessimization" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (56 commits) KVM: nVMX: cleanup and fix host 64-bit mode checks KVM: vmx: fix build warnings in hv_enable_direct_tlbflush() on i386 KVM: x86: Don't check kvm_rebooting in __kvm_handle_fault_on_reboot() KVM: x86: Drop ____kvm_handle_fault_on_reboot() KVM: VMX: Add error handling to VMREAD helper KVM: VMX: Optimize VMX instruction error and fault handling KVM: x86: Check kvm_rebooting in kvm_spurious_fault() KVM: selftests: fix ucall on x86 Revert "locking/pvqspinlock: Don't wait if vCPU is preempted" kvm: nvmx: limit atomic switch MSRs kvm: svm: Intercept RDPRU kvm: x86: Add "significant index" flag to a few CPUID leaves KVM: x86/mmu: Skip invalid pages during zapping iff root_count is zero KVM: x86/mmu: Explicitly track only a single invalid mmu generation KVM: x86/mmu: Revert "KVM: x86/mmu: Remove is_obsolete() call" KVM: x86/mmu: Revert "Revert "KVM: MMU: reclaim the zapped-obsolete page first"" KVM: x86/mmu: Revert "Revert "KVM: MMU: collapse TLB flushes when zap all pages"" KVM: x86/mmu: Revert "Revert "KVM: MMU: zap pages in batch"" KVM: x86/mmu: Revert "Revert "KVM: MMU: add tracepoint for kvm_mmu_invalidate_all_pages"" KVM: x86/mmu: Revert "Revert "KVM: MMU: show mmu_valid_gen in shadow page related tracepoints"" ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/virt/kvm/api.txt13
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/api.txt b/Documentation/virt/kvm/api.txt
index 136f1eef3712..4833904d32a5 100644
--- a/Documentation/virt/kvm/api.txt
+++ b/Documentation/virt/kvm/api.txt
@@ -5309,3 +5309,16 @@ Architectures: x86
This capability indicates that KVM supports paravirtualized Hyper-V IPI send
hypercalls:
HvCallSendSyntheticClusterIpi, HvCallSendSyntheticClusterIpiEx.
+8.21 KVM_CAP_HYPERV_DIRECT_TLBFLUSH
+
+Architecture: x86
+
+This capability indicates that KVM running on top of Hyper-V hypervisor
+enables Direct TLB flush for its guests meaning that TLB flush
+hypercalls are handled by Level 0 hypervisor (Hyper-V) bypassing KVM.
+Due to the different ABI for hypercall parameters between Hyper-V and
+KVM, enabling this capability effectively disables all hypercall
+handling by KVM (as some KVM hypercall may be mistakenly treated as TLB
+flush hypercalls by Hyper-V) so userspace should disable KVM identification
+in CPUID and only exposes Hyper-V identification. In this case, guest
+thinks it's running on Hyper-V and only use Hyper-V hypercalls.

Privacy Policy