Add helper functions to centralize guest MSR read and write emulation.
This change consolidates the MSR emulation logic and makes it easier
to extend support for new MSR-related VM exit reasons introduced with
the immediate form of MSR instructions.
Signed-off-by: Xin Li (Intel) <xin@xxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/x86.c | 67 +++++++++++++++++++++++----------
2 files changed, 49 insertions(+), 19 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f19a76d3ca0e..a854d9a166fe 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -201,6 +201,7 @@ enum kvm_reg {
VCPU_EXREG_SEGMENTS,
VCPU_EXREG_EXIT_INFO_1,
VCPU_EXREG_EXIT_INFO_2,
+ VCPU_EXREG_EDX_EAX,
};
enum {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a1c49bc681c4..5086c3b30345 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2024,54 +2024,71 @@ static int kvm_msr_user_space(struct kvm_vcpu *vcpu, u32 index,
return 1;
}
-int kvm_emulate_rdmsr(struct kvm_vcpu *vcpu)
+static int kvm_emulate_get_msr(struct kvm_vcpu *vcpu, u32 msr, int reg)
{
- u32 ecx = kvm_rcx_read(vcpu);
u64 data;
int r;
- r = kvm_get_msr_with_filter(vcpu, ecx, &data);
+ r = kvm_get_msr_with_filter(vcpu, msr, &data);
if (!r) {
- trace_kvm_msr_read(ecx, data);
+ trace_kvm_msr_read(msr, data);
- kvm_rax_write(vcpu, data & -1u);
- kvm_rdx_write(vcpu, (data >> 32) & -1u);
+ if (reg == VCPU_EXREG_EDX_EAX) {
+ kvm_rax_write(vcpu, data & -1u);
+ kvm_rdx_write(vcpu, (data >> 32) & -1u);
+ } else {
+ kvm_register_write(vcpu, reg, data);
+ }
} else {
/* MSR read failed? See if we should ask user space */
- if (kvm_msr_user_space(vcpu, ecx, KVM_EXIT_X86_RDMSR, 0,
+ if (kvm_msr_user_space(vcpu, msr, KVM_EXIT_X86_RDMSR, 0,
complete_fast_rdmsr, r))
return 0;
- trace_kvm_msr_read_ex(ecx);
+ trace_kvm_msr_read_ex(msr);
}
return kvm_x86_call(complete_emulated_msr)(vcpu, r);
}
+
+int kvm_emulate_rdmsr(struct kvm_vcpu *vcpu)
+{
+ return kvm_emulate_get_msr(vcpu, kvm_rcx_read(vcpu), VCPU_EXREG_EDX_EAX);
+}
EXPORT_SYMBOL_GPL(kvm_emulate_rdmsr);
-int kvm_emulate_wrmsr(struct kvm_vcpu *vcpu)
+static int kvm_emulate_set_msr(struct kvm_vcpu *vcpu, u32 msr, int reg)
{
- u32 ecx = kvm_rcx_read(vcpu);
- u64 data = kvm_read_edx_eax(vcpu);
+ u64 data;
int r;
- r = kvm_set_msr_with_filter(vcpu, ecx, data);
+ if (reg == VCPU_EXREG_EDX_EAX)
+ data = kvm_read_edx_eax(vcpu);
+ else
+ data = kvm_register_read(vcpu, reg);
+
+ r = kvm_set_msr_with_filter(vcpu, msr, data);
if (!r) {
- trace_kvm_msr_write(ecx, data);
+ trace_kvm_msr_write(msr, data);
} else {
/* MSR write failed? See if we should ask user space */
- if (kvm_msr_user_space(vcpu, ecx, KVM_EXIT_X86_WRMSR, data,
+ if (kvm_msr_user_space(vcpu, msr, KVM_EXIT_X86_WRMSR, data,
complete_fast_msr_access, r))
return 0;
/* Signal all other negative errors to userspace */
if (r < 0)
return r;
- trace_kvm_msr_write_ex(ecx, data);
+ trace_kvm_msr_write_ex(msr, data);
}
return kvm_x86_call(complete_emulated_msr)(vcpu, r);
}
+
+int kvm_emulate_wrmsr(struct kvm_vcpu *vcpu)
+{
+ return kvm_emulate_set_msr(vcpu, kvm_rcx_read(vcpu), VCPU_EXREG_EDX_EAX);
+}
EXPORT_SYMBOL_GPL(kvm_emulate_wrmsr);
int kvm_emulate_as_nop(struct kvm_vcpu *vcpu)
@@ -2163,9 +2180,8 @@ static int handle_fastpath_set_tscdeadline(struct kvm_vcpu *vcpu, u64 data)
return 0;
}
-fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu)
+static fastpath_t handle_set_msr_irqoff(struct kvm_vcpu *vcpu, u32 msr, int reg)
{
- u32 msr = kvm_rcx_read(vcpu);
u64 data;
fastpath_t ret;
bool handled;
@@ -2174,11 +2190,19 @@ fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu)
switch (msr) {
case APIC_BASE_MSR + (APIC_ICR >> 4):
- data = kvm_read_edx_eax(vcpu);
+ if (reg == VCPU_EXREG_EDX_EAX)
+ data = kvm_read_edx_eax(vcpu);
+ else
+ data = kvm_register_read(vcpu, reg);
+
handled = !handle_fastpath_set_x2apic_icr_irqoff(vcpu, data);
break;
case MSR_IA32_TSC_DEADLINE:
- data = kvm_read_edx_eax(vcpu);
+ if (reg == VCPU_EXREG_EDX_EAX)
+ data = kvm_read_edx_eax(vcpu);
+ else
+ data = kvm_register_read(vcpu, reg);
+
handled = !handle_fastpath_set_tscdeadline(vcpu, data);
break;
default:
@@ -2200,6 +2224,11 @@ fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu)
return ret;
}
+
+fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu)
+{
+ return handle_set_msr_irqoff(vcpu, kvm_rcx_read(vcpu), VCPU_EXREG_EDX_EAX);
+}
EXPORT_SYMBOL_GPL(handle_fastpath_set_msr_irqoff);
/*
--
2.50.1
