[PATCH 02/26] KVM: x86: Take an unsigned 32-bit int for has_emulated_msr()'s index

Sean Christopherson
2020-01-29T23:48:50Z

Take a u32 for the index in has_emulated_msr() to match hardware, which
treats MSR indices as unsigned 32-bit values. Functionally, taking a
signed int doesn't cause problems with the current code base, but could
theoretically cause problems with 32-bit KVM, e.g. if the index were
checked via a less-than statement, which would evaluate incorrectly for
MSR indices with bit 31 set.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/svm.c | 2 +-
arch/x86/kvm/vmx/vmx.c | 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 77d206a93658..5c2ad3fa0980 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1050,7 +1050,7 @@ struct kvm_x86_ops {
int (*hardware_setup)(void); /* __init */
void (*hardware_unsetup)(void); /* __exit */
bool (*cpu_has_accelerated_tpr)(void);
- bool (*has_emulated_msr)(int index);
+ bool (*has_emulated_msr)(u32 index);
void (*cpuid_update)(struct kvm_vcpu *vcpu);

struct kvm *(*vm_alloc)(void);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index bf0556588ad0..a7b944a3a0e2 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -5985,7 +5985,7 @@ static bool svm_cpu_has_accelerated_tpr(void)
return false;
}

-static bool svm_has_emulated_msr(int index)
+static bool svm_has_emulated_msr(u32 index)
{
switch (index) {
case MSR_IA32_MCG_EXT_CTL:
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 1419c53aed16..f5bb1ad2e9fa 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6274,7 +6274,7 @@ static void vmx_handle_exit_irqoff(struct kvm_vcpu *vcpu,
*exit_fastpath = handle_fastpath_set_msr_irqoff(vcpu);
}

-static bool vmx_has_emulated_msr(int index)
+static bool vmx_has_emulated_msr(u32 index)
{
switch (index) {
case MSR_IA32_SMBASE:
--
2.24.1