| Message ID | 20210203004035.101292-3-krish.sadhukhan@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: nSVM: Check addresses of MSR bitmap and IO bitmap tables on vmrun of nested guests | expand |
On 03/02/21 01:40, Krish Sadhukhan wrote: > According to section "Canonicalization and Consistency Checks" in APM vol 2, > the following guest state is illegal: > > "The MSR or IOIO intercept tables extend to a physical address that > is greater than or equal to the maximum supported physical address." > > Also check that these addresses are aligned on page boundary. > > Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com> > --- > arch/x86/kvm/svm/nested.c | 20 ++++++++++++++------ > 1 file changed, 14 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c > index 7a605ad8254d..caf285e643db 100644 > --- a/arch/x86/kvm/svm/nested.c > +++ b/arch/x86/kvm/svm/nested.c > @@ -214,7 +214,8 @@ static bool svm_get_nested_state_pages(struct kvm_vcpu *vcpu) > return true; > } > > -static bool nested_vmcb_check_controls(struct vmcb_control_area *control) > +static bool nested_vmcb_check_controls(struct kvm_vcpu *vcpu, > + struct vmcb_control_area *control) > { > if ((vmcb_is_intercept(control, INTERCEPT_VMRUN)) == 0) > return false; > @@ -226,10 +227,17 @@ static bool nested_vmcb_check_controls(struct vmcb_control_area *control) > !npt_enabled) > return false; > > + if (!page_address_valid(vcpu, control->msrpm_base_pa + > + MSRPM_ALLOC_ORDER * PAGE_SIZE)) > + return false; > + if (!page_address_valid(vcpu, control->iopm_base_pa + > + IOPM_ALLOC_ORDER * PAGE_SIZE)) There are four problems: 1) The value does not have to be page-aligned 2) you also have an off-by-one here, the value to be checked is the last byte of the previous page 3) ORDER is a shift count not a number of pages 4) there could be an overflow 1-3 can be fixed by something like this: if (!page_address_valid(vcpu, PAGE_ALIGN(control->xyz_pa) + ((PAGE_SIZE << XYZ_ALLOC_ORDER) - 1))); but it's even better to extract everything to a new function and not use page_address_valid at all. static inline nested_check_pa(struct kvm_vcpu *vcpu, uint64_t pa, unsigned int order) { uint64_t last_pa = PAGE_ALIGN(pa) + (PAGE_SIZE << order) - 1; return last_pa > pa && !(last_pa >> cpuid_maxphyaddr(vcpu)); } Paolo > + return false; > + > return true; > } > > -static bool nested_vmcb_checks(struct vcpu_svm *svm, struct vmcb *vmcb12) > +static bool nested_vmcb_checks(struct kvm_vcpu *vcpu, struct vmcb *vmcb12) > { > bool vmcb12_lma; > > @@ -258,10 +266,10 @@ static bool nested_vmcb_checks(struct vcpu_svm *svm, struct vmcb *vmcb12) > (vmcb12->save.cr3 & MSR_CR3_LONG_MBZ_MASK)) > return false; > } > - if (!kvm_is_valid_cr4(&svm->vcpu, vmcb12->save.cr4)) > + if (!kvm_is_valid_cr4(vcpu, vmcb12->save.cr4)) > return false; > > - return nested_vmcb_check_controls(&vmcb12->control); > + return nested_vmcb_check_controls(vcpu, &vmcb12->control); > } > > static void load_nested_vmcb_control(struct vcpu_svm *svm, > @@ -488,7 +496,7 @@ int nested_svm_vmrun(struct vcpu_svm *svm) > if (WARN_ON_ONCE(!svm->nested.initialized)) > return -EINVAL; > > - if (!nested_vmcb_checks(svm, vmcb12)) { > + if (!nested_vmcb_checks(&svm->vcpu, vmcb12)) { > vmcb12->control.exit_code = SVM_EXIT_ERR; > vmcb12->control.exit_code_hi = 0; > vmcb12->control.exit_info_1 = 0; > @@ -1176,7 +1184,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, > goto out_free; > > ret = -EINVAL; > - if (!nested_vmcb_check_controls(ctl)) > + if (!nested_vmcb_check_controls(vcpu, ctl)) > goto out_free; > > /* >
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 7a605ad8254d..caf285e643db 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -214,7 +214,8 @@ static bool svm_get_nested_state_pages(struct kvm_vcpu *vcpu) return true; } -static bool nested_vmcb_check_controls(struct vmcb_control_area *control) +static bool nested_vmcb_check_controls(struct kvm_vcpu *vcpu, + struct vmcb_control_area *control) { if ((vmcb_is_intercept(control, INTERCEPT_VMRUN)) == 0) return false; @@ -226,10 +227,17 @@ static bool nested_vmcb_check_controls(struct vmcb_control_area *control) !npt_enabled) return false; + if (!page_address_valid(vcpu, control->msrpm_base_pa + + MSRPM_ALLOC_ORDER * PAGE_SIZE)) + return false; + if (!page_address_valid(vcpu, control->iopm_base_pa + + IOPM_ALLOC_ORDER * PAGE_SIZE)) + return false; + return true; } -static bool nested_vmcb_checks(struct vcpu_svm *svm, struct vmcb *vmcb12) +static bool nested_vmcb_checks(struct kvm_vcpu *vcpu, struct vmcb *vmcb12) { bool vmcb12_lma; @@ -258,10 +266,10 @@ static bool nested_vmcb_checks(struct vcpu_svm *svm, struct vmcb *vmcb12) (vmcb12->save.cr3 & MSR_CR3_LONG_MBZ_MASK)) return false; } - if (!kvm_is_valid_cr4(&svm->vcpu, vmcb12->save.cr4)) + if (!kvm_is_valid_cr4(vcpu, vmcb12->save.cr4)) return false; - return nested_vmcb_check_controls(&vmcb12->control); + return nested_vmcb_check_controls(vcpu, &vmcb12->control); } static void load_nested_vmcb_control(struct vcpu_svm *svm, @@ -488,7 +496,7 @@ int nested_svm_vmrun(struct vcpu_svm *svm) if (WARN_ON_ONCE(!svm->nested.initialized)) return -EINVAL; - if (!nested_vmcb_checks(svm, vmcb12)) { + if (!nested_vmcb_checks(&svm->vcpu, vmcb12)) { vmcb12->control.exit_code = SVM_EXIT_ERR; vmcb12->control.exit_code_hi = 0; vmcb12->control.exit_info_1 = 0; @@ -1176,7 +1184,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, goto out_free; ret = -EINVAL; - if (!nested_vmcb_check_controls(ctl)) + if (!nested_vmcb_check_controls(vcpu, ctl)) goto out_free; /*
According to section "Canonicalization and Consistency Checks" in APM vol 2, the following guest state is illegal: "The MSR or IOIO intercept tables extend to a physical address that is greater than or equal to the maximum supported physical address." Also check that these addresses are aligned on page boundary. Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com> --- arch/x86/kvm/svm/nested.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-)