From 1dc35dacc16b4f13547125c5df2d026d9e46ea01 Mon Sep 17 00:00:00 2001 From: Ladi Prosek Date: Wed, 30 Nov 2016 16:03:11 +0100 Subject: [PATCH] KVM: nVMX: check host CR3 on vmentry and vmexit MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This commit adds missing host CR3 checks. Before entering guest mode, the value of CR3 is checked for reserved bits. After returning, nested_vmx_load_cr3 is called to set the new CR3 value and check and load PDPTRs. Signed-off-by: Ladi Prosek Signed-off-by: Radim Krčmář --- arch/x86/include/uapi/asm/vmx.h | 1 + arch/x86/kvm/vmx.c | 25 ++++++++++++++++++------- 2 files changed, 19 insertions(+), 7 deletions(-) diff --git a/arch/x86/include/uapi/asm/vmx.h b/arch/x86/include/uapi/asm/vmx.h index f9dea4fd4107..14458658e988 100644 --- a/arch/x86/include/uapi/asm/vmx.h +++ b/arch/x86/include/uapi/asm/vmx.h @@ -133,6 +133,7 @@ { EXIT_REASON_XRSTORS, "XRSTORS" } #define VMX_ABORT_SAVE_GUEST_MSR_FAIL 1 +#define VMX_ABORT_LOAD_HOST_PDPTE_FAIL 2 #define VMX_ABORT_LOAD_HOST_MSR_FAIL 4 #endif /* _UAPIVMX_H */ diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index a0d6e59f4f34..7280a355737e 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -9968,6 +9968,14 @@ static int nested_vmx_store_msr(struct kvm_vcpu *vcpu, u64 gpa, u32 count) return 0; } +static bool nested_cr3_valid(struct kvm_vcpu *vcpu, unsigned long val) +{ + unsigned long invalid_mask; + + invalid_mask = (~0ULL) << cpuid_maxphyaddr(vcpu); + return (val & invalid_mask) == 0; +} + /* * Load guest's/host's cr3 at nested entry/exit. nested_ept is true if we are * emulating VM entry into a guest with EPT enabled. @@ -9977,11 +9985,8 @@ static int nested_vmx_store_msr(struct kvm_vcpu *vcpu, u64 gpa, u32 count) static int nested_vmx_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, bool nested_ept, unsigned long *entry_failure_code) { - unsigned long invalid_mask; - if (cr3 != kvm_read_cr3(vcpu) || (!nested_ept && pdptrs_changed(vcpu))) { - invalid_mask = (~0ULL) << cpuid_maxphyaddr(vcpu); - if (cr3 & invalid_mask) { + if (!nested_cr3_valid(vcpu, cr3)) { *entry_failure_code = ENTRY_FAIL_DEFAULT; return 1; } @@ -10452,7 +10457,8 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) } if (!nested_host_cr0_valid(vcpu, vmcs12->host_cr0) || - !nested_host_cr4_valid(vcpu, vmcs12->host_cr4)) { + !nested_host_cr4_valid(vcpu, vmcs12->host_cr4) || + !nested_cr3_valid(vcpu, vmcs12->host_cr3)) { nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_HOST_STATE_FIELD); goto out; @@ -10879,6 +10885,7 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) { struct kvm_segment seg; + unsigned long entry_failure_code; if (vmcs12->vm_exit_controls & VM_EXIT_LOAD_IA32_EFER) vcpu->arch.efer = vmcs12->host_ia32_efer; @@ -10916,8 +10923,12 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu, nested_ept_uninit_mmu_context(vcpu); - kvm_set_cr3(vcpu, vmcs12->host_cr3); - kvm_mmu_reset_context(vcpu); + /* + * Only PDPTE load can fail as the value of cr3 was checked on entry and + * couldn't have changed. + */ + if (nested_vmx_load_cr3(vcpu, vmcs12->host_cr3, false, &entry_failure_code)) + nested_vmx_abort(vcpu, VMX_ABORT_LOAD_HOST_PDPTE_FAIL); if (!enable_ept) vcpu->arch.walk_mmu->inject_page_fault = kvm_inject_page_fault; -- 2.20.1