From 4988e000b3a8fba70cc31ce826829bb6cf8c7838 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Tue, 12 Oct 2021 11:07:59 -0400
Subject: [PATCH] KVM: SEV-ES: fix length of string I/O
Git-commit: 019057bd73d1751fdfec41e43148baf3303d98f9
Patch-mainline: v5.15-rc7
References: stable-5.14.15

commit 019057bd73d1751fdfec41e43148baf3303d98f9 upstream.

The size of the data in the scratch buffer is not divided by the size of
each port I/O operation, so vcpu->arch.pio.count ends up being larger
than it should be by a factor of size.

Cc: stable@vger.kernel.org
Fixes: 7ed9abfe8e9f ("KVM: SVM: Support string IO operations for an SEV-ES guest")
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 arch/x86/kvm/svm/sev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 4fd8ae3d4915..b7b0c34d9761 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2591,7 +2591,7 @@ int sev_es_string_io(struct vcpu_svm *svm, int size, unsigned int port, int in)
 		return -EINVAL;
 
 	return kvm_sev_es_string_io(&svm->vcpu, size, port,
-				    svm->ghcb_sa, svm->ghcb_sa_len, in);
+				    svm->ghcb_sa, svm->ghcb_sa_len / size, in);
 }
 
 void sev_es_init_vmcb(struct vcpu_svm *svm)
-- 
2.26.2