From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Cc: Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Borislav Petkov <bp@suse.de>,
Tom Lendacky <thomas.lendacky@amd.com>,
Brijesh Singh <brijesh.singh@amd.com>
Subject: [PATCH v4 14/14] KVM: SVM: Skip SEV cache flush if no ASIDs have been used
Date: Fri, 5 Mar 2021 17:59:05 -0800 [thread overview]
Message-ID: <20210306015905.186698-15-seanjc@google.com> (raw)
In-Reply-To: <20210306015905.186698-1-seanjc@google.com>
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(-)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 3bf04a697723..f8ebda7c365a 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -57,9 +57,14 @@ 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,
@@ -81,14 +86,7 @@ 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 */
@@ -1399,10 +1397,11 @@ 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)
--
2.30.1.766.gb4fecdf3b7-goog
prev parent reply other threads:[~2021-03-06 2:00 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-06 1:58 [PATCH v4 00/14] KVM: SVM: Misc SEV cleanups Sean Christopherson
2021-03-06 1:58 ` [PATCH v4 01/14] KVM: SVM: Zero out the VMCB array used to track SEV ASID association Sean Christopherson
2021-03-06 1:58 ` [PATCH v4 02/14] KVM: SVM: Free sev_asid_bitmap during init if SEV setup fails Sean Christopherson
2021-03-06 1:58 ` [PATCH v4 03/14] KVM: SVM: Move SEV module params/variables to sev.c Sean Christopherson
2021-03-06 1:58 ` [PATCH v4 04/14] KVM: x86: Do not advertise SME, VM_PAGE_FLUSH, or unknown features Sean Christopherson
2021-03-06 1:58 ` [PATCH v4 05/14] x86/sev: Drop redundant and potentially misleading 'sev_enabled' Sean Christopherson
2021-03-06 1:58 ` [PATCH v4 06/14] KVM: SVM: Append "_enabled" to module-scoped SEV/SEV-ES control variables Sean Christopherson
2021-03-06 1:58 ` [PATCH v4 07/14] KVM: SVM: Condition sev_enabled and sev_es_enabled on CONFIG_KVM_AMD_SEV=y Sean Christopherson
2021-03-06 1:58 ` [PATCH v4 08/14] KVM: SVM: Enable SEV/SEV-ES functionality by default (when supported) Sean Christopherson
2021-03-06 1:59 ` [PATCH v4 09/14] KVM: SVM: Unconditionally invoke sev_hardware_teardown() Sean Christopherson
2021-03-06 1:59 ` [PATCH v4 10/14] KVM: SVM: Explicitly check max SEV ASID during sev_hardware_setup() Sean Christopherson
2021-03-06 1:59 ` [PATCH v4 11/14] KVM: SVM: Move SEV VMCB tracking allocation to sev.c Sean Christopherson
2021-03-06 1:59 ` [PATCH v4 12/14] KVM: SVM: Drop redundant svm_sev_enabled() helper Sean Christopherson
2021-03-06 1:59 ` [PATCH v4 13/14] KVM: SVM: Remove an unnecessary prototype declaration of sev_flush_asids() Sean Christopherson
2021-03-06 1:59 ` Sean Christopherson [this message]
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