[PATCH 08/12] kvm: svm: move has_svm() code to asm/virtext.h

Eduardo Habkost
2008-11-17T21:03:20Z

Use a trick to keep the printk()s on has_svm() working as before. gcc
will take care of not generating code for the 'msg' stuff when the
function is called with a NULL msg argument.

Signed-off-by: Eduardo Habkost <ehabkost-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
arch/x86/include/asm/virtext.h | 41 ++++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/svm.c | 19 ++++-------------
2 files changed, 46 insertions(+), 14 deletions(-)

diff --git a/arch/x86/include/asm/virtext.h b/arch/x86/include/asm/virtext.h
index 6bcf0ac..6f0d409 100644
--- a/arch/x86/include/asm/virtext.h
+++ b/arch/x86/include/asm/virtext.h
@@ -19,6 +19,7 @@
#include <asm/system.h>

#include <asm/vmx.h>
+#include <asm/svm.h>

/*
* VMX functions:
@@ -66,4 +67,44 @@ static inline void cpu_emergency_vmxoff(void)
__cpu_emergency_vmxoff();
}

+
+
+
+/*
+ * SVM functions:
+ */
+
+/** Check if the CPU has SVM support
+ *
+ * You can use the 'msg' arg to get a message describing the problem,
+ * if the function returns zero. Simply pass NULL if you are not interested
+ * on the messages; gcc should take care of not generating code for
+ * the messages on this case.
+ */
+static inline int cpu_has_svm(const char **msg)
+{
+ uint32_t eax, ebx, ecx, edx;
+
+ if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
+ if (msg)
+ *msg = "not amd";
+ return 0;
+ }
+
+ cpuid(0x80000000, &eax, &ebx, &ecx, &edx);
+ if (eax < SVM_CPUID_FUNC) {
+ if (msg)
+ *msg = "can't execute cpuid_8000000a";
+ return 0;
+ }
+
+ cpuid(0x80000001, &eax, &ebx, &ecx, &edx);
+ if (!(ecx & (1 << SVM_CPUID_FEATURE_SHIFT))) {
+ if (msg)
+ *msg = "svm not available";
+ return 0;
+ }
+ return 1;
+}
+
#endif /* _ASM_X86_VIRTEX_H */
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 9c4ce65..64241f5 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -28,6 +28,8 @@

#include <asm/desc.h>

+#include <asm/virtext.h>
+
#define __ex(x) __kvm_handle_fault_on_reboot(x)

MODULE_AUTHOR("Qumranet");
@@ -245,24 +247,13 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu)

static int has_svm(void)
{
- uint32_t eax, ebx, ecx, edx;
-
- if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
- printk(KERN_INFO "has_svm: not amd\n");
- return 0;
- }
+ const char *msg;

- cpuid(0x80000000, &eax, &ebx, &ecx, &edx);
- if (eax < SVM_CPUID_FUNC) {
- printk(KERN_INFO "has_svm: can't execute cpuid_8000000a\n");
+ if (!cpu_has_svm(&msg)) {
+ printk(KERN_INFO "has_svn: %s\n", msg);
return 0;
}

- cpuid(0x80000001, &eax, &ebx, &ecx, &edx);
- if (!(ecx & (1 << SVM_CPUID_FEATURE_SHIFT))) {
- printk(KERN_DEBUG "has_svm: svm not available\n");
- return 0;
- }
return 1;
}

--
1.5.5.GIT