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    SubjectRe: [PATCH v2 2/2] Revert "KVM: x86: work around leak of uninitialized stack contents"
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    On 05/06/20 13:59, Vitaly Kuznetsov wrote:
    > handle_vmptrst()/handle_vmread() stopped injecting #PF unconditionally
    > and switched to nested_vmx_handle_memory_failure() which just kills the
    > guest with KVM_EXIT_INTERNAL_ERROR in case of MMIO access, zeroing
    > 'exception' in kvm_write_guest_virt_system() is not needed anymore.
    >
    > This reverts commit 541ab2aeb28251bf7135c7961f3a6080eebcc705.
    >
    > Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
    > ---
    > arch/x86/kvm/x86.c | 7 -------
    > 1 file changed, 7 deletions(-)
    >
    > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
    > index 9e41b5135340..0097a97d331f 100644
    > --- a/arch/x86/kvm/x86.c
    > +++ b/arch/x86/kvm/x86.c
    > @@ -5647,13 +5647,6 @@ int kvm_write_guest_virt_system(struct kvm_vcpu *vcpu, gva_t addr, void *val,
    > /* kvm_write_guest_virt_system can pull in tons of pages. */
    > vcpu->arch.l1tf_flush_l1d = true;
    >
    > - /*
    > - * FIXME: this should call handle_emulation_failure if X86EMUL_IO_NEEDED
    > - * is returned, but our callers are not ready for that and they blindly
    > - * call kvm_inject_page_fault. Ensure that they at least do not leak
    > - * uninitialized kernel stack memory into cr2 and error code.
    > - */
    > - memset(exception, 0, sizeof(*exception));
    > return kvm_write_guest_virt_helper(addr, val, bytes, vcpu,
    > PFERR_WRITE_MASK, exception);
    > }
    >

    Queued, thanks.

    Paolo

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