KVM: x86: extend "struct x86_emulate_ops" with "get_cpuid"

commit bdb42f5afebe208eae90406959383856ae2caf2b upstream

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]

[bwh: Backport to 2.6.32:
 - Don't use emul_to_vcpu
 - Adjust context]

Signed-off-by: Stephan Baerwolf <stephan.baerwolf@tu-ilmenau.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 5ed59ec92534124348301c54403277f02c8459e2..61bf2ebee3ba2bbe6eb75acf6e08a17b1f2ce2d1 100644 (file)
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -109,6 +109,8 @@ struct x86_emulate_ops {
                                unsigned int bytes,
                                struct kvm_vcpu *vcpu);
 
+       bool (*get_cpuid)(struct x86_emulate_ctxt *ctxt,
+                        u32 *eax, u32 *ebx, u32 *ecx, u32 *edx);
 };
 
 /* Type, address-of, and value of an instruction's operand. */

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index df1cefb9457d74658782a420408cdb25f102545c..23b5a71fbc54c5a08ce57bc1d331718ed45884b8 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2871,12 +2871,35 @@ void kvm_report_emulation_failure(struct kvm_vcpu *vcpu, const char *context)
 }
 EXPORT_SYMBOL_GPL(kvm_report_emulation_failure);
 
+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(ctxt->vcpu,
+                                           *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,
        .fetch               = kvm_fetch_guest_virt,
        .read_emulated       = emulator_read_emulated,
        .write_emulated      = emulator_write_emulated,
        .cmpxchg_emulated    = emulator_cmpxchg_emulated,
+       .get_cpuid           = emulator_get_cpuid,
 };
 
 static void cache_all_regs(struct kvm_vcpu *vcpu)