On 08/07/20 16:00, Vitaly Kuznetsov wrote:
> OVMF booted guest running on shadow pages crashes on TRIPLE FAULT after
> enabling paging from SMM. The crash is triggered from mmu_check_root() and
> is caused by kvm_is_visible_gfn() searching through memslots with as_id = 0
> while vCPU may be in a different context (address space).
>
> Introduce kvm_vcpu_is_visible_gfn() and use it from mmu_check_root().
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> ---
> arch/x86/kvm/mmu/mmu.c | 2 +-
> include/linux/kvm_host.h | 1 +
> virt/kvm/kvm_main.c | 8 ++++++++
> 3 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 4fd4b5de8996..309024210a35 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -3668,7 +3668,7 @@ static int mmu_check_root(struct kvm_vcpu *vcpu, gfn_t root_gfn)
> {
> int ret = 0;
>
> - if (!kvm_is_visible_gfn(vcpu->kvm, root_gfn)) {
> + if (!kvm_vcpu_is_visible_gfn(vcpu, root_gfn)) {
> kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
> ret = 1;
> }
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index d564855243d8..f74d2a5afc26 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -774,6 +774,7 @@ int kvm_clear_guest_page(struct kvm *kvm, gfn_t gfn, int offset, int len);
> int kvm_clear_guest(struct kvm *kvm, gpa_t gpa, unsigned long len);
> struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn);
> bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn);
> +bool kvm_vcpu_is_visible_gfn(struct kvm_vcpu *vcpu, gfn_t gfn);
> unsigned long kvm_host_page_size(struct kvm_vcpu *vcpu, gfn_t gfn);
> void mark_page_dirty(struct kvm *kvm, gfn_t gfn);
>
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index a852af5c3214..b131c7da1d12 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -1626,6 +1626,14 @@ bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
> }
> EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);
>
> +bool kvm_vcpu_is_visible_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
> +{
> + struct kvm_memory_slot *memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
> +
> + return kvm_is_visible_memslot(memslot);
> +}
> +EXPORT_SYMBOL_GPL(kvm_vcpu_is_visible_gfn);
> +
> unsigned long kvm_host_page_size(struct kvm_vcpu *vcpu, gfn_t gfn)
> {
> struct vm_area_struct *vma;
>
Queued, thanks.
Paolo
