From 37486135d3a7b03acc7755b63627a130437f066a Mon Sep 17 00:00:00 2001 From: Babu Moger Date: Tue, 12 May 2020 18:59:06 -0500 Subject: KVM: x86: Fix pkru save/restore when guest CR4.PKE=0, move it to x86.c Though rdpkru and wrpkru are contingent upon CR4.PKE, the PKRU resource isn't. It can be read with XSAVE and written with XRSTOR. So, if we don't set the guest PKRU value here(kvm_load_guest_xsave_state), the guest can read the host value. In case of kvm_load_host_xsave_state, guest with CR4.PKE clear could potentially use XRSTOR to change the host PKRU value. While at it, move pkru state save/restore to common code and the host_pkru field to kvm_vcpu_arch. This will let SVM support protection keys. Cc: stable@vger.kernel.org Reported-by: Jim Mattson Signed-off-by: Babu Moger Message-Id: <158932794619.44260.14508381096663848853.stgit@naples-babu.amd.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'arch/x86/kvm/x86.c') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 98176b80c481..d11eba8b85c6 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -837,11 +837,25 @@ void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu) vcpu->arch.ia32_xss != host_xss) wrmsrl(MSR_IA32_XSS, vcpu->arch.ia32_xss); } + + if (static_cpu_has(X86_FEATURE_PKU) && + (kvm_read_cr4_bits(vcpu, X86_CR4_PKE) || + (vcpu->arch.xcr0 & XFEATURE_MASK_PKRU)) && + vcpu->arch.pkru != vcpu->arch.host_pkru) + __write_pkru(vcpu->arch.pkru); } EXPORT_SYMBOL_GPL(kvm_load_guest_xsave_state); void kvm_load_host_xsave_state(struct kvm_vcpu *vcpu) { + if (static_cpu_has(X86_FEATURE_PKU) && + (kvm_read_cr4_bits(vcpu, X86_CR4_PKE) || + (vcpu->arch.xcr0 & XFEATURE_MASK_PKRU))) { + vcpu->arch.pkru = rdpkru(); + if (vcpu->arch.pkru != vcpu->arch.host_pkru) + __write_pkru(vcpu->arch.host_pkru); + } + if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE)) { if (vcpu->arch.xcr0 != host_xcr0) @@ -3549,6 +3563,9 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) kvm_x86_ops.vcpu_load(vcpu, cpu); + /* Save host pkru register if supported */ + vcpu->arch.host_pkru = read_pkru(); + /* Apply any externally detected TSC adjustments (due to suspend) */ if (unlikely(vcpu->arch.tsc_offset_adjustment)) { adjust_tsc_offset_host(vcpu, vcpu->arch.tsc_offset_adjustment); -- cgit v1.2.3