KVM: x86: only copy XSAVE state for the supported features

[linux-2.6-block.git] / arch / x86 / kvm / cpuid.c

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 5a5ff94fef652fecc9bedfd56e46fefbb4d5352b..0a1e3b8b964de8e42ebbc41adbd3c67a8c938dd4 100644 (file)
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -23,6 +23,26 @@
 #include "mmu.h"
 #include "trace.h"
 
+static u32 xstate_required_size(u64 xstate_bv)
+{
+       int feature_bit = 0;
+       u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
+
+       xstate_bv &= ~XSTATE_FPSSE;
+       while (xstate_bv) {
+               if (xstate_bv & 0x1) {
+                       u32 eax, ebx, ecx, edx;
+                       cpuid_count(0xD, feature_bit, &eax, &ebx, &ecx, &edx);
+                       ret = max(ret, eax + ebx);
+               }
+
+               xstate_bv >>= 1;
+               feature_bit++;
+       }
+
+       return ret;
+}
+
 void kvm_update_cpuid(struct kvm_vcpu *vcpu)
 {
        struct kvm_cpuid_entry2 *best;
@@ -47,12 +67,16 @@ void kvm_update_cpuid(struct kvm_vcpu *vcpu)
        }
 
        best = kvm_find_cpuid_entry(vcpu, 0xD, 0);
-       if (!best)
+       if (!best) {
                vcpu->arch.guest_supported_xcr0 = 0;
-       else
+               vcpu->arch.guest_xstate_size = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
+       } else {
                vcpu->arch.guest_supported_xcr0 =
                        (best->eax | ((u64)best->edx << 32)) &
                        host_xcr0 & KVM_SUPPORTED_XCR0;
+               vcpu->arch.guest_xstate_size =
+                       xstate_required_size(vcpu->arch.guest_supported_xcr0);
+       }
 
        kvm_pmu_cpuid_update(vcpu);
 }