From 2259c17f01887666220a35619c44c576aeed2a30 Mon Sep 17 00:00:00 2001 From: Jim Mattson Date: Thu, 29 Oct 2020 10:06:48 -0700 Subject: kvm: x86: Sink cpuid update into vendor-specific set_cr4 functions On emulated VM-entry and VM-exit, update the CPUID bits that reflect CR4.OSXSAVE and CR4.PKE. This fixes a bug where the CPUID bits could continue to reflect L2 CR4 values after emulated VM-exit to L1. It also fixes a related bug where the CPUID bits could continue to reflect L1 CR4 values after emulated VM-entry to L2. The latter bug is mainly relevant to SVM, wherein CPUID is not a required intercept. However, it could also be relevant to VMX, because the code to conditionally update these CPUID bits assumes that the guest CPUID and the guest CR4 are always in sync. Fixes: 8eb3f87d903168 ("KVM: nVMX: fix guest CR4 loading when emulating L2 to L1 exit") Fixes: 2acf923e38fb6a ("KVM: VMX: Enable XSAVE/XRSTOR for guest") Fixes: b9baba86148904 ("KVM, pkeys: expose CPUID/CR4 to guest") Reported-by: Abhiroop Dabral Signed-off-by: Jim Mattson Reviewed-by: Ricardo Koller Reviewed-by: Peter Shier Cc: Haozhong Zhang Cc: Dexuan Cui Cc: Huaitong Han Message-Id: <20201029170648.483210-1-jmattson@google.com> --- arch/x86/kvm/vmx/vmx.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/x86/kvm/vmx/vmx.c') diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 2b6d538454a6..c3441e7e5a87 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -3113,6 +3113,7 @@ static bool vmx_is_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) { + unsigned long old_cr4 = vcpu->arch.cr4; struct vcpu_vmx *vmx = to_vmx(vcpu); /* * Pass through host's Machine Check Enable value to hw_cr4, which @@ -3169,6 +3170,9 @@ void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) vmcs_writel(CR4_READ_SHADOW, cr4); vmcs_writel(GUEST_CR4, hw_cr4); + + if ((cr4 ^ old_cr4) & (X86_CR4_OSXSAVE | X86_CR4_PKE)) + kvm_update_cpuid_runtime(vcpu); } void vmx_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg) -- cgit v1.2.3