linux-kernel - [PATCH v3 02/13] KVM: SVM: Free sev_asid_bitmap during init if SEV setup fails

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Message-Id: <20210122202144.2756381-3-seanjc@google.com>
Date:   Fri, 22 Jan 2021 12:21:33 -0800
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Borislav Petkov <bp@...e.de>,
        Tom Lendacky <thomas.lendacky@....com>,
        Brijesh Singh <brijesh.singh@....com>
Subject: [PATCH v3 02/13] KVM: SVM: Free sev_asid_bitmap during init if SEV
 setup fails

Free sev_asid_bitmap if the reclaim bitmap allocation fails, othwerise
KVM will unnecessarily keep the bitmap when SEV is not fully enabled.

Freeing the page is also necessary to avoid introducing a bug when a
future patch eliminates svm_sev_enabled() in favor of using the global
'sev' flag directly.  While sev_hardware_enabled() checks max_sev_asid,
which is true even if KVM setup fails, 'sev' will be true if and only
if KVM setup fully succeeds.

Fixes: 33af3a7ef9e6 ("KVM: SVM: Reduce WBINVD/DF_FLUSH invocations")
Cc: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/svm/sev.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index c8ffdbc81709..ec742dabbd5b 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1274,8 +1274,11 @@ void __init sev_hardware_setup(void)
 		goto out;
 
 	sev_reclaim_asid_bitmap = bitmap_zalloc(max_sev_asid, GFP_KERNEL);
-	if (!sev_reclaim_asid_bitmap)
+	if (!sev_reclaim_asid_bitmap) {
+		bitmap_free(sev_asid_bitmap);
+		sev_asid_bitmap = NULL;
 		goto out;
+	}
 
 	pr_info("SEV supported: %u ASIDs\n", max_sev_asid - min_sev_asid + 1);
 	sev_supported = true;
-- 
2.30.0.280.ga3ce27912f-goog