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| author | Sean Christopherson <seanjc@google.com> | 2021-04-21 19:11:25 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-04-26 05:27:17 -0400 |
| commit | 469bb32b68d5a414fea293c17b532329c6dc9612 (patch) | |
| tree | 41833bf693c816cfcb2828f15f12e26b8ab312ff /arch/x86 | |
| parent | 82b7ae0481aeed393094e4f73bf4566a504b86bc (diff) | |
| download | linux-469bb32b68d5a414fea293c17b532329c6dc9612.tar.gz | |
KVM: SVM: Skip SEV cache flush if no ASIDs have been used
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> Message-Id: <20210422021125.3417167-16-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/svm/sev.c | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index fd3ffc103ed8..a9d8d6aafdb8 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -74,9 +74,15 @@ struct enc_region { unsigned long size; }; -static int sev_flush_asids(void) +/* Called with the sev_bitmap_lock held, or on shutdown */ +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_asid, min_asid); + if (pos >= max_asid) + return -EBUSY; /* * DEACTIVATE will clear the WBINVD indicator causing DF_FLUSH to fail, @@ -103,14 +109,7 @@ static inline bool is_mirroring_enc_context(struct kvm *kvm) /* 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 */ @@ -1897,12 +1896,14 @@ 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); + misc_cg_set_capacity(MISC_CG_RES_SEV, 0); misc_cg_set_capacity(MISC_CG_RES_SEV_ES, 0); - - sev_flush_asids(); } int sev_cpu_init(struct svm_cpu_data *sd) |