Re: KVM: nested VMX: disable perf cpuid reporting
On Thu, Sep 18, 2014 at 06:24:57PM -0300, Marcelo Tosatti wrote:
Initilization of L2 guest with -cpu host, on L1 guest with -cpu host
triggers:
(qemu) KVM: entry failed, hardware error 0x7
...
nested_vmx_run: VMCS MSR_{LOAD,STORE} unsupported
Nested VMX MSR load/store support is not sufficient to
allow perf for L2 guest.
Until properly fixed, trap CPUID and disable function 0xA.
Signed-off-by: Marcelo Tosatti mtosa...@redhat.com
Ping, Paolo?
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Re: KVM: nested VMX: disable perf cpuid reporting
Il 22/09/2014 21:01, Marcelo Tosatti ha scritto:
On Thu, Sep 18, 2014 at 06:24:57PM -0300, Marcelo Tosatti wrote:
Initilization of L2 guest with -cpu host, on L1 guest with -cpu host
triggers:
(qemu) KVM: entry failed, hardware error 0x7
...
nested_vmx_run: VMCS MSR_{LOAD,STORE} unsupported
Nested VMX MSR load/store support is not sufficient to
allow perf for L2 guest.
Until properly fixed, trap CPUID and disable function 0xA.
Signed-off-by: Marcelo Tosatti mtosa...@redhat.com
Ping, Paolo?
Sorry, didn't push to kvm/queue but I've already applied the patch
locally. I will do it first thing tomorrow (my workstation is off right
now so I cannot send you a SHA).
Paolo
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Re: KVM: nested VMX: disable perf cpuid reporting
Il 18/09/2014 23:24, Marcelo Tosatti ha scritto:
Initilization of L2 guest with -cpu host, on L1 guest with -cpu host
triggers:
(qemu) KVM: entry failed, hardware error 0x7
...
nested_vmx_run: VMCS MSR_{LOAD,STORE} unsupported
Nested VMX MSR load/store support is not sufficient to
allow perf for L2 guest.
Until properly fixed, trap CPUID and disable function 0xA.
Signed-off-by: Marcelo Tosatti mtosa...@redhat.com
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index e28d798..976e3a5 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -774,6 +774,12 @@ void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32
*ebx, u32 *ecx, u32 *edx)
if (!best)
best = check_cpuid_limit(vcpu, function, index);
+ /*
+ * Perfmon not yet supported for L2 guest.
+ */
+ if (is_guest_mode(vcpu) function == 0xa)
+ best = NULL;
+
if (best) {
*eax = best-eax;
*ebx = best-ebx;
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e8f08e9..2ab5047 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6986,6 +6986,8 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu
*vcpu)
case EXIT_REASON_TASK_SWITCH:
return 1;
case EXIT_REASON_CPUID:
+ if (kvm_register_read(vcpu, VCPU_REGS_RAX) == 0xa)
+ return 0;
return 1;
case EXIT_REASON_HLT:
return nested_cpu_has(vmcs12, CPU_BASED_HLT_EXITING);
Nice solution. :)
Paolo
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