linux-kernel - [PATCH] KVM: SEV-ES: reduce ghcb_sa

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Message-Id: <20211018105231.517041-1-pbonzini@redhat.com>
Date:   Mon, 18 Oct 2021 06:52:31 -0400
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     stable@...r.kernel.org, Naresh Kamboju <naresh.kamboju@...aro.org>
Subject: [PATCH] KVM: SEV-ES: reduce ghcb_sa_len to 32 bits

The size of the GHCB scratch area is limited to 16 KiB (GHCB_SCRATCH_AREA_LIMIT),
so there is no need for it to be a u64.  This fixes a build error on 32-bit
systems:

i686-linux-gnu-ld: arch/x86/kvm/svm/sev.o: in function `sev_es_string_io:
sev.c:(.text+0x110f): undefined reference to `__udivdi3'

Cc: stable@...r.kernel.org
Fixes: 019057bd73d1 ("KVM: SEV-ES: fix length of string I/O")
Reported-by: Naresh Kamboju <naresh.kamboju@...aro.org>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/svm/svm.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 128a54b1fbf1..5d30db599e10 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -191,7 +191,7 @@ struct vcpu_svm {
 
 	/* SEV-ES scratch area support */
 	void *ghcb_sa;
-	u64 ghcb_sa_len;
+	u32 ghcb_sa_len;
 	bool ghcb_sa_sync;
 	bool ghcb_sa_free;
 
-- 
2.27.0