xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

KVM/Hyper-V: Add new KVM capability KVM_CAP_HYPERV_DIRECT_TLBFLUSH

Browse Source 
Hyper-V direct tlb flush function should be enabled for
guest that only uses Hyper-V hypercall. User space
hypervisor(e.g, Qemu) can disable KVM identification in
CPUID and just exposes Hyper-V identification to make
sure the precondition. Add new KVM capability KVM_CAP_
HYPERV_DIRECT_TLBFLUSH for user space to enable Hyper-V
direct tlb function and this function is default to be
disabled in KVM.

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Tianyu Lan
2019-08-22 22:30:20 +08:00
committed by Paolo Bonzini
parent 7a83247e01
commit 344c6c8047
4 changed files with 23 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
Documentation/virt/kvm/api.txt
View File

@@ -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.