Patchwork [Oneiric,1/2] KVM: x86: extend "struct x86_emulate_ops" with "get_cpuid"

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Submitter Stefan Bader
Date March 14, 2012, 10:18 p.m.
Message ID <1331763526-32743-8-git-send-email-stefan.bader@canonical.com>
Download mbox | patch
Permalink /patch/146748/
State New
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Stefan Bader - March 14, 2012, 10:18 p.m.
From eaee58e1433e1b16e686cfcdcbc207d4310a239f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stephan=20B=C3=A4rwolf?= <stephan.baerwolf@tu-ilmenau.de>
Date: Thu, 12 Jan 2012 16:43:03 +0100
Subject: [PATCH 7/8] KVM: x86: extend "struct x86_emulate_ops" with
 "get_cpuid"

In order to be able to proceed checks on CPU-specific properties
within the emulator, function "get_cpuid" is introduced.
With "get_cpuid" it is possible to virtually call the guests
"cpuid"-opcode without changing the VM's context.

[mtosatti: cleanup/beautify code]

Signed-off-by: Stephan Baerwolf <stephan.baerwolf@tu-ilmenau.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

CVE-2012-0045
BugLink: http://bugs.launchpad.net/bugs/917842
(cherry-picked from commit bdb42f5afebe208eae90406959383856ae2caf2b upstream)
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
---
 arch/x86/include/asm/kvm_emulate.h |    3 +++
 arch/x86/kvm/x86.c                 |   23 +++++++++++++++++++++++
 2 files changed, 26 insertions(+), 0 deletions(-)

Patch

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 0049211..18e54f1 100644
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -189,6 +189,9 @@  struct x86_emulate_ops {
 	int (*intercept)(struct x86_emulate_ctxt *ctxt,
 			 struct x86_instruction_info *info,
 			 enum x86_intercept_stage stage);
+
+	bool (*get_cpuid)(struct x86_emulate_ctxt *ctxt,
+			 u32 *eax, u32 *ebx, u32 *ecx, u32 *edx);
 };
 
 typedef u32 __attribute__((vector_size(16))) sse128_t;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bc58ede..8e15578 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4436,6 +4436,28 @@  static int emulator_intercept(struct x86_emulate_ctxt *ctxt,
 	return kvm_x86_ops->check_intercept(emul_to_vcpu(ctxt), info, stage);
 }
 
+static bool emulator_get_cpuid(struct x86_emulate_ctxt *ctxt,
+			       u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
+{
+	struct kvm_cpuid_entry2 *cpuid = NULL;
+
+	if (eax && ecx)
+		cpuid = kvm_find_cpuid_entry(emul_to_vcpu(ctxt),
+					    *eax, *ecx);
+
+	if (cpuid) {
+		*eax = cpuid->eax;
+		*ecx = cpuid->ecx;
+		if (ebx)
+			*ebx = cpuid->ebx;
+		if (edx)
+			*edx = cpuid->edx;
+		return true;
+	}
+
+	return false;
+}
+
 static struct x86_emulate_ops emulate_ops = {
 	.read_std            = kvm_read_guest_virt_system,
 	.write_std           = kvm_write_guest_virt_system,
@@ -4466,6 +4488,7 @@  static struct x86_emulate_ops emulate_ops = {
 	.get_fpu             = emulator_get_fpu,
 	.put_fpu             = emulator_put_fpu,
 	.intercept           = emulator_intercept,
+	.get_cpuid           = emulator_get_cpuid,
 };
 
 static void cache_all_regs(struct kvm_vcpu *vcpu)