[PATCH 3.12 013/133] x86, kvm: correctly access the KVM_CPUID_FEATURES leaf at 0x40000101

Greg Kroah-Hartman
2014-02-04T21:08:10Z

From: Paolo Bonzini <pbonzini@redhat.com>

commit 77f01bdfa5e55dc19d3eb747181d2730a9bb3ca8 upstream.

When Hyper-V hypervisor leaves are present, KVM must relocate
its own leaves at 0x40000100, because Windows does not look for
Hyper-V leaves at indices other than 0x40000000. In this case,
the KVM features are at 0x40000101, but the old code would always
look at 0x40000001.

Fix by using kvm_cpuid_base(). This also requires making the
function non-inline, since kvm_cpuid_base() is static.

Fixes: 1085ba7f552d84aa8ac0ae903fa8d0cc2ff9f79d
Cc: mtosatti@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/include/asm/kvm_para.h | 11 ++++++-----
arch/x86/kernel/kvm.c | 5 +++++
2 files changed, 11 insertions(+), 5 deletions(-)

--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -85,13 +85,9 @@ static inline long kvm_hypercall4(unsign
return ret;
}

-static inline unsigned int kvm_arch_para_features(void)
-{
- return cpuid_eax(KVM_CPUID_FEATURES);
-}
-
#ifdef CONFIG_KVM_GUEST
bool kvm_para_available(void);
+unsigned int kvm_arch_para_features(void);
void __init kvm_guest_init(void);
void kvm_async_pf_task_wait(u32 token);
void kvm_async_pf_task_wake(u32 token);
@@ -115,6 +111,11 @@ static inline bool kvm_para_available(vo
{
return 0;
}
+
+static inline unsigned int kvm_arch_para_features(void)
+{
+ return 0;
+}

static inline u32 kvm_read_and_reset_pf_reason(void)
{
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -527,6 +527,11 @@ bool kvm_para_available(void)
}
EXPORT_SYMBOL_GPL(kvm_para_available);

+unsigned int kvm_arch_para_features(void)
+{
+ return cpuid_eax(kvm_cpuid_base() | KVM_CPUID_FEATURES);
+}
+
static uint32_t __init kvm_detect(void)
{
return kvm_cpuid_base();