github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-06-01 19:13:47 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

KVM: SVM: Skip SEV cache flush if no ASIDs have been used

Browse Source 
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>
This commit is contained in:
Sean Christopherson 2021-04-21 19:11:25 -07:00 committed by Paolo Bonzini
parent 82b7ae0481
commit 469bb32b68
1 changed files with 13 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
arch/x86/kvm/svm/sev.c
View File

@ -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)