On 22/04/21 04:11, Sean Christopherson wrote:
+ 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;
There's a tiny bug here which would cause sev_flush_asids to return 0
if there are reclaimed SEV ASIDs and the caller is looking for an SEV-ES
ASID, or vice versa. The bug used to be in __sev_recycle_asids, you're
just moving the code.
It's not a big deal because sev_asid_new only retries once, but we might
as well fix it:
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 02b3426a9e39..403c6991e67c 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -74,12 +74,13 @@ struct enc_region {
unsigned long size;
};
+/* Called with the sev_bitmap_lock held, or on shutdown */
static int sev_flush_asids(int min_asid, int max_asid)
{
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);
+ pos = find_next_bit(sev_reclaim_asid_bitmap, max_asid, min_asid);
if (pos >= max_asid)
return -EBUSY;
Paolo
/*
* DEACTIVATE will clear the WBINVD indicator causing DF_FLUSH to fail,
@@ -87,14 +92,7 @@ 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 */
@@ -1846,10 +1844,11 @@ 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)
