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@xxxxxxxxxx>
Reviewed-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
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)
