[PATCH 07/11] kvm: svm: move has_svm() code to asm/virtext.h

Eduardo Habkost
2008-11-13T17:44:37Z

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@redhat.com>
---
arch/x86/include/asm/virtext.h | 33 +++++++++++++++++++++++++++++++++
arch/x86/kvm/svm.c | 19 +++++--------------
2 files changed, 38 insertions(+), 14 deletions(-)

diff --git a/arch/x86/include/asm/virtext.h b/arch/x86/include/asm/virtext.h
index f6adf9d..e900015 100644
--- a/arch/x86/include/asm/virtext.h
+++ b/arch/x86/include/asm/virtext.h
@@ -95,4 +95,37 @@ static inline void cpu_emergency_vmxoff(void)

#define SVM_VM_CR_SVM_DISABLE 4

+/** 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;