linux-kernel - [PATCH 5.14 111/169] KVM: SEV-ES: reduce ghcb_sa

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Date:   Mon, 25 Oct 2021 21:14:52 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Naresh Kamboju <naresh.kamboju@...aro.org>,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: [PATCH 5.14 111/169] KVM: SEV-ES: reduce ghcb_sa_len to 32 bits

From: Paolo Bonzini <pbonzini@...hat.com>

commit 9f1ee7b169afbd10c3ad254220d1b37beb5798aa upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/x86/kvm/svm/svm.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- 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;