Messages in this thread | | | Date | Thu, 16 Feb 2023 03:20:38 +0700 | Subject | Re: [PATCH v2 3/3] KVM: SVM: WARN if GATag generation drops VM or vCPU ID information | From | "Suthikulpanit, Suravee" <> |
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On 2/7/2023 7:21 AM, Sean Christopherson wrote: > WARN if generating a GATag given a VM ID and vCPU ID doesn't yield the > same IDs when pulling the IDs back out of the tag. Don't bother adding > error handling to callers, this is very much a paranoid sanity check as > KVM fully controls the VM ID and is supposed to reject too-big vCPU IDs. > > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > arch/x86/kvm/svm/avic.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c > index 326341a22153..cfc8ab773025 100644 > --- a/arch/x86/kvm/svm/avic.c > +++ b/arch/x86/kvm/svm/avic.c > @@ -43,12 +43,21 @@ > #define AVIC_VM_ID_SHIFT HWEIGHT32(AVIC_PHYSICAL_MAX_INDEX_MASK) > #define AVIC_VM_ID_MASK (GENMASK(31, AVIC_VM_ID_SHIFT) >> AVIC_VM_ID_SHIFT) > > -#define AVIC_GATAG(x, y) (((x & AVIC_VM_ID_MASK) << AVIC_VM_ID_SHIFT) | \ > - (y & AVIC_VCPU_ID_MASK)) > #define AVIC_GATAG_TO_VMID(x) ((x >> AVIC_VM_ID_SHIFT) & AVIC_VM_ID_MASK) > #define AVIC_GATAG_TO_VCPUID(x) (x & AVIC_VCPU_ID_MASK) > > -static_assert(AVIC_GATAG(AVIC_VM_ID_MASK, AVIC_VCPU_ID_MASK) == -1u); > +#define __AVIC_GATAG(vm_id, vcpu_id) ((((vm_id) & AVIC_VM_ID_MASK) << AVIC_VM_ID_SHIFT) | \ > + ((vcpu_id) & AVIC_VCPU_ID_MASK)) > +#define AVIC_GATAG(vm_id, vcpu_id) \ > +({ \ > + u32 ga_tag = __AVIC_GATAG(vm_id, vcpu_id); \ > + \ > + WARN_ON_ONCE(AVIC_GATAG_TO_VCPUID(ga_tag) != (vcpu_id)); \ > + WARN_ON_ONCE(AVIC_GATAG_TO_VMID(ga_tag) != (vm_id)); \ > + ga_tag; \ > +}) > + > +static_assert(__AVIC_GATAG(AVIC_VM_ID_MASK, AVIC_VCPU_ID_MASK) == -1u); > > static bool force_avic; > module_param_unsafe(force_avic, bool, 0444);
Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Thanks, Suravee
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