Refactor em_{rdmsr,wrmsr} to allow an MSR to bounce to userspace when it
exists in the list of MSRs userspace has requested to manage with the
ioctl KVM_SET_EXIT_MSRS.
Signed-off-by: Aaron Lewis <aaronlewis@xxxxxxxxxx>
Based-on-patch-by: Alexander Graf <graf@xxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 18 +++++++++--
arch/x86/kvm/x86.c | 70 ++++++++++++++++++++++++++++++------------
2 files changed, 66 insertions(+), 22 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index d0e2825ae617..744ab9c92b73 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3689,11 +3689,18 @@ static int em_dr_write(struct x86_emulate_ctxt *ctxt)
static int em_wrmsr(struct x86_emulate_ctxt *ctxt)
{
+ u64 msr_index = reg_read(ctxt, VCPU_REGS_RCX);
u64 msr_data;
+ int r;
msr_data = (u32)reg_read(ctxt, VCPU_REGS_RAX)
| ((u64)reg_read(ctxt, VCPU_REGS_RDX) << 32);
- if (ctxt->ops->set_msr(ctxt, reg_read(ctxt, VCPU_REGS_RCX), msr_data))
+ r = ctxt->ops->set_msr(ctxt, msr_index, msr_data);
+
+ if (r == X86EMUL_IO_NEEDED)
+ return r;
+
+ if (r)
return emulate_gp(ctxt, 0);
return X86EMUL_CONTINUE;
@@ -3701,9 +3708,16 @@ static int em_wrmsr(struct x86_emulate_ctxt *ctxt)
static int em_rdmsr(struct x86_emulate_ctxt *ctxt)
{
+ u64 msr_index = reg_read(ctxt, VCPU_REGS_RCX);
u64 msr_data;
+ int r;
+
+ r = ctxt->ops->get_msr(ctxt, msr_index, &msr_data);
+
+ if (r == X86EMUL_IO_NEEDED)
+ return r;
- if (ctxt->ops->get_msr(ctxt, reg_read(ctxt, VCPU_REGS_RCX), &msr_data))
+ if (r)
return emulate_gp(ctxt, 0);
*reg_write(ctxt, VCPU_REGS_RAX) = (u32)msr_data;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 47619b49818a..4dff6147557e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1590,21 +1590,46 @@ static int complete_userspace_wrmsr(struct kvm_vcpu *vcpu)
return complete_userspace_msr(vcpu, true);
}
+static int kvm_get_msr_user(struct kvm_vcpu *vcpu, u32 index)
+{
+ if (!kvm_msr_user_exit(vcpu->kvm, index))
+ return 0;
+
+ vcpu->run->exit_reason = KVM_EXIT_X86_RDMSR;
+ vcpu->run->msr.index = index;
+ vcpu->run->msr.data = 0;
+ vcpu->run->msr.inject_gp = 0;
+ memset(vcpu->run->msr.pad, 0, sizeof(vcpu->run->msr.pad));
+ vcpu->arch.complete_userspace_io =
+ complete_userspace_rdmsr;
+
+ return 1;
+}
+
+static int kvm_set_msr_user(struct kvm_vcpu *vcpu, u32 index, u64 data)
+{
+ if (!kvm_msr_user_exit(vcpu->kvm, index))
+ return 0;
+
+ vcpu->run->exit_reason = KVM_EXIT_X86_WRMSR;
+ vcpu->run->msr.index = index;
+ vcpu->run->msr.data = data;
+ vcpu->run->msr.inject_gp = 0;
+ memset(vcpu->run->msr.pad, 0, sizeof(vcpu->run->msr.pad));
+ vcpu->arch.complete_userspace_io =
+ complete_userspace_wrmsr;
+
+ return 1;
+}
+
int kvm_emulate_rdmsr(struct kvm_vcpu *vcpu)
{
u32 ecx = kvm_rcx_read(vcpu);
u64 data;
- if (kvm_msr_user_exit(vcpu->kvm, ecx)) {
- vcpu->run->exit_reason = KVM_EXIT_X86_RDMSR;
- vcpu->run->msr.index = ecx;
- vcpu->run->msr.data = 0;
- vcpu->run->msr.inject_gp = 0;
- memset(vcpu->run->msr.pad, 0, sizeof(vcpu->run->msr.pad));
- vcpu->arch.complete_userspace_io =
- complete_userspace_rdmsr;
+ if (kvm_get_msr_user(vcpu, ecx))
+ /* Bounce to user space */
return 0;
- }
if (kvm_get_msr(vcpu, ecx, &data)) {
trace_kvm_msr_read_ex(ecx);
@@ -1625,16 +1650,9 @@ int kvm_emulate_wrmsr(struct kvm_vcpu *vcpu)
u32 ecx = kvm_rcx_read(vcpu);
u64 data = kvm_read_edx_eax(vcpu);
- if (kvm_msr_user_exit(vcpu->kvm, ecx)) {
- vcpu->run->exit_reason = KVM_EXIT_X86_WRMSR;
- vcpu->run->msr.index = ecx;
- vcpu->run->msr.data = data;
- vcpu->run->msr.inject_gp = 0;
- memset(vcpu->run->msr.pad, 0, sizeof(vcpu->run->msr.pad));
- vcpu->arch.complete_userspace_io =
- complete_userspace_wrmsr;
+ if (kvm_set_msr_user(vcpu, ecx, data))
+ /* Bounce to user space */
return 0;
- }
if (kvm_set_msr(vcpu, ecx, data)) {
trace_kvm_msr_write_ex(ecx, data);
@@ -6442,13 +6460,25 @@ static void emulator_set_segment(struct x86_emulate_ctxt *ctxt, u16 selector,
static int emulator_get_msr(struct x86_emulate_ctxt *ctxt,
u32 msr_index, u64 *pdata)
{
- return kvm_get_msr(emul_to_vcpu(ctxt), msr_index, pdata);
+ struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
+
+ if (kvm_get_msr_user(vcpu, msr_index))
+ /* Bounce to user space */
+ return X86EMUL_IO_NEEDED;
+
+ return kvm_get_msr(vcpu, msr_index, pdata);
}
static int emulator_set_msr(struct x86_emulate_ctxt *ctxt,
u32 msr_index, u64 data)
{
- return kvm_set_msr(emul_to_vcpu(ctxt), msr_index, data);
+ struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
+
+ if (kvm_set_msr_user(vcpu, msr_index, data))
+ /* Bounce to user space */
+ return X86EMUL_IO_NEEDED;
+
+ return kvm_set_msr(vcpu, msr_index, data);
}
static u64 emulator_get_smbase(struct x86_emulate_ctxt *ctxt)
--
2.28.0.236.gb10cc79966-goog
