[v3.2.y 1/2] KVM: x86: extend "struct x86_emulate_ops" with "get_cpuid"

[Stefan Bader]

>From 993480c661c6a850fcb79ac06137208950415170 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stephan=20B=C3=A4rwolf?= <stephan.baerw...@tu-ilmenau.de>
Date: Thu, 12 Jan 2012 16:43:03 +0100
Subject: [PATCH 09/10] 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.baerw...@tu-ilmenau.de>
Signed-off-by: Marcelo Tosatti <mtosa...@redhat.com>

(cherry-picked from commit bdb42f5afebe208eae90406959383856ae2caf2b upstream)
Signed-off-by: Stefan Bader <stefan.ba...@canonical.com>
---
 arch/x86/include/asm/kvm_emulate.h |    3 +++
 arch/x86/kvm/x86.c                 |   23 +++++++++++++++++++++++
 2 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/kvm_emulate.h 
b/arch/x86/include/asm/kvm_emulate.h
index a026507..a440a7f 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 4c938da..e04cae1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4655,6 +4655,28 @@ 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,
@@ -4685,6 +4707,7 @@ 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)
-- 
1.7.9.1

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