| Message ID | 20210122202144.2756381-14-seanjc@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: SVM: Misc SEV cleanups | expand |
On 1/22/21 2:21 PM, Sean Christopherson wrote: > Skip SEV's expensive WBINVD and DF_FLUSH if there are no SEV ASIDs > waiting to be reclaimed, e.g. if SEV was never used. This "fixes" an > issue where the DF_FLUSH fails during hardware teardown if the original > SEV_INIT failed. Ideally, SEV wouldn't be marked as enabled in KVM if > SEV_INIT fails, but that's a problem for another day. > > Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> > --- > arch/x86/kvm/svm/sev.c | 23 +++++++++++------------ > 1 file changed, 11 insertions(+), 12 deletions(-) > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index 73da2af1e25d..0a4715e60b88 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -56,9 +56,14 @@ struct enc_region { > unsigned long size; > }; > > -static int sev_flush_asids(void) > +static int sev_flush_asids(int min_asid, int max_asid) > { > - int ret, error = 0; > + int ret, pos, error = 0; > + > + /* Check if there are any ASIDs to reclaim before performing a flush */ > + pos = find_next_bit(sev_reclaim_asid_bitmap, max_sev_asid, min_asid); > + if (pos >= max_asid) > + return -EBUSY; > > /* > * DEACTIVATE will clear the WBINVD indicator causing DF_FLUSH to fail, > @@ -80,14 +85,7 @@ static int sev_flush_asids(void) > /* Must be called with the sev_bitmap_lock held */ > static bool __sev_recycle_asids(int min_asid, int max_asid) > { > - int pos; > - > - /* Check if there are any ASIDs to reclaim before performing a flush */ > - pos = find_next_bit(sev_reclaim_asid_bitmap, max_sev_asid, min_asid); > - if (pos >= max_asid) > - return false; > - > - if (sev_flush_asids()) > + if (sev_flush_asids(min_asid, max_asid)) > return false; > > /* The flush process will flush all reclaimable SEV and SEV-ES ASIDs */ > @@ -1324,10 +1322,11 @@ void sev_hardware_teardown(void) > if (!sev_enabled) > return; > > + /* No need to take sev_bitmap_lock, all VMs have been destroyed. */ > + sev_flush_asids(0, max_sev_asid); > + > bitmap_free(sev_asid_bitmap); > bitmap_free(sev_reclaim_asid_bitmap); > - > - sev_flush_asids(); > } > > int sev_cpu_init(struct svm_cpu_data *sd) >
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 73da2af1e25d..0a4715e60b88 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -56,9 +56,14 @@ struct enc_region { unsigned long size; }; -static int sev_flush_asids(void) +static int sev_flush_asids(int min_asid, int max_asid) { - int ret, error = 0; + int ret, pos, error = 0; + + /* Check if there are any ASIDs to reclaim before performing a flush */ + pos = find_next_bit(sev_reclaim_asid_bitmap, max_sev_asid, min_asid); + if (pos >= max_asid) + return -EBUSY; /* * DEACTIVATE will clear the WBINVD indicator causing DF_FLUSH to fail, @@ -80,14 +85,7 @@ static int sev_flush_asids(void) /* Must be called with the sev_bitmap_lock held */ static bool __sev_recycle_asids(int min_asid, int max_asid) { - int pos; - - /* Check if there are any ASIDs to reclaim before performing a flush */ - pos = find_next_bit(sev_reclaim_asid_bitmap, max_sev_asid, min_asid); - if (pos >= max_asid) - return false; - - if (sev_flush_asids()) + if (sev_flush_asids(min_asid, max_asid)) return false; /* The flush process will flush all reclaimable SEV and SEV-ES ASIDs */ @@ -1324,10 +1322,11 @@ void sev_hardware_teardown(void) if (!sev_enabled) return; + /* No need to take sev_bitmap_lock, all VMs have been destroyed. */ + sev_flush_asids(0, max_sev_asid); + bitmap_free(sev_asid_bitmap); bitmap_free(sev_reclaim_asid_bitmap); - - sev_flush_asids(); } int sev_cpu_init(struct svm_cpu_data *sd)
Skip SEV's expensive WBINVD and DF_FLUSH if there are no SEV ASIDs waiting to be reclaimed, e.g. if SEV was never used. This "fixes" an issue where the DF_FLUSH fails during hardware teardown if the original SEV_INIT failed. Ideally, SEV wouldn't be marked as enabled in KVM if SEV_INIT fails, but that's a problem for another day. Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/svm/sev.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-)