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| author | Arbel Moshe <arbel.moshe@oracle.com> | 2018-03-12 13:12:53 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2018-03-16 22:02:01 +0100 |
| commit | 2d7921c499afebac78b13ab9a3758261a97e07b7 (patch) | |
| tree | 9fbeb2ebc8c352acdbaab0c13857de719467a76b /arch/x86/kvm/emulate.c | |
| parent | 9718420e9fd462ac6b7ea840f9e63eb6af7e1bda (diff) | |
| download | linux-2d7921c499afebac78b13ab9a3758261a97e07b7.tar.bz2 | |
KVM: x86: Add support for VMware backdoor Pseudo-PMCs
VMware exposes the following Pseudo PMCs:
0x10000: Physical host TSC
0x10001: Elapsed real time in ns
0x10002: Elapsed apparent time in ns
For more info refer to:
https://www.vmware.com/files/pdf/techpaper/Timekeeping-In-VirtualMachines.pdf
VMware allows access to these Pseduo-PMCs even when read via RDPMC
in Ring3 and CR4.PCE=0. Therefore, commit modifies x86 emulator
to allow access to these PMCs in this situation. In addition,
emulation of these PMCs were added to kvm_pmu_rdpmc().
Signed-off-by: Arbel Moshe <arbel.moshe@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/emulate.c')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 821f6335cbcb..dd88158a0eed 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -30,6 +30,7 @@ #include "x86.h" #include "tss.h" #include "mmu.h" +#include "pmu.h" /* * Operand types @@ -4293,6 +4294,13 @@ static int check_rdpmc(struct x86_emulate_ctxt *ctxt) u64 cr4 = ctxt->ops->get_cr(ctxt, 4); u64 rcx = reg_read(ctxt, VCPU_REGS_RCX); + /* + * VMware allows access to these Pseduo-PMCs even when read via RDPMC + * in Ring3 when CR4.PCE=0. + */ + if (enable_vmware_backdoor && is_vmware_backdoor_pmc(rcx)) + return X86EMUL_CONTINUE; + if ((!(cr4 & X86_CR4_PCE) && ctxt->ops->cpl(ctxt)) || ctxt->ops->check_pmc(ctxt, rcx)) return emulate_gp(ctxt, 0); |