lkml.org 
[lkml]   [2022]   [Jun]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH Part2 v6 47/49] *fix for stale per-cpu pointer due to cond_resched during ghcb mapping
    On Mon, Jun 20, 2022 at 5:15 PM Ashish Kalra <Ashish.Kalra@amd.com> wrote:
    >
    > From: Michael Roth <michael.roth@amd.com>
    >
    > Signed-off-by: Michael Roth <michael.roth@amd.com>

    Can you add a commit description here? Is this a fix for existing
    SEV-ES support or should this be incorporated into a patch in this
    series which adds this issue?

    > ---
    > arch/x86/kvm/svm/svm.c | 6 +++++-
    > 1 file changed, 5 insertions(+), 1 deletion(-)
    >
    > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
    > index fced6ea423ad..f78e3b1bde0e 100644
    > --- a/arch/x86/kvm/svm/svm.c
    > +++ b/arch/x86/kvm/svm/svm.c
    > @@ -1352,7 +1352,7 @@ static void svm_vcpu_free(struct kvm_vcpu *vcpu)
    > static void svm_prepare_switch_to_guest(struct kvm_vcpu *vcpu)
    > {
    > struct vcpu_svm *svm = to_svm(vcpu);
    > - struct svm_cpu_data *sd = per_cpu(svm_data, vcpu->cpu);
    > + struct svm_cpu_data *sd;
    >
    > if (sev_es_guest(vcpu->kvm))
    > sev_es_unmap_ghcb(svm);
    > @@ -1360,6 +1360,10 @@ static void svm_prepare_switch_to_guest(struct kvm_vcpu *vcpu)
    > if (svm->guest_state_loaded)
    > return;
    >
    > + /* sev_es_unmap_ghcb() can resched, so grab per-cpu pointer afterward. */
    > + barrier();
    > + sd = per_cpu(svm_data, vcpu->cpu);
    > +
    > /*
    > * Save additional host state that will be restored on VMEXIT (sev-es)
    > * or subsequent vmload of host save area.
    > --
    > 2.25.1
    >

    \
     
     \ /
      Last update: 2022-06-24 18:37    [W:4.210 / U:0.248 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site