linux-kernel - [PATCH 01/33] KVM: SVM: support writing 0 to K8 performance counter control registers

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1199630379-28638-2-git-send-email-avi@qumranet.com>
Date:	Sun,  6 Jan 2008 16:39:07 +0200
From:	Avi Kivity <avi@...ranet.com>
To:	linux-kernel@...r.kernel.org, kvm-devel@...ts.sourceforge.net
Cc:	Joerg Roedel <joerg.roedel@....com>
Subject: [PATCH 01/33] KVM: SVM: support writing 0 to K8 performance counter control registers

From: Joerg Roedel <joerg.roedel@....com>

This lets SVM ignore writes of the value 0 to the performance counter control
registers.  Thus enabling them will still fail in the guest, but a write of 0
which keeps them disabled is accepted.  This is required to boot Windows
Vista 64bit.

[avi: avoid fall-thru in switch statement]

Signed-off-by: Joerg Roedel <joerg.roedel@....com>
Signed-off-by: Markus Rechberger <markus.rechberger@....com>
Signed-off-by: Avi Kivity <avi@...ranet.com>
---
 drivers/kvm/svm.c |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index 9f8564a..839a75f 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -1155,7 +1155,20 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data)
 	case MSR_IA32_SYSENTER_ESP:
 		svm->vmcb->save.sysenter_esp = data;
 		break;
+	case MSR_K7_EVNTSEL0:
+	case MSR_K7_EVNTSEL1:
+	case MSR_K7_EVNTSEL2:
+	case MSR_K7_EVNTSEL3:
+		/*
+		 * only support writing 0 to the performance counters for now
+		 * to make Windows happy. Should be replaced by a real
+		 * performance counter emulation later.
+		 */
+		if (data != 0)
+			goto unhandled;
+		break;
 	default:
+	unhandled:
 		return kvm_set_msr_common(vcpu, ecx, data);
 	}
 	return 0;
-- 
1.5.3.7

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/