[PATCH v2 3/5] KVM: X86: setup residency msrs during vCPU creation

[Wanpeng Li <kernellwp@gmail.com>]

From: Wanpeng Li <wanpengli@tencent.com>

To setup core residency msrs during vCPU creation. Allowing guest reads 
CORE cstate when exposing host CPU power management capabilities to the 
guest. PKG cstate is restricted currently to avoid a guest to get the 
whole package information in multi-tenant scenario.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
 arch/x86/kvm/vmx/vmx.c |  2 ++
 arch/x86/kvm/x86.c     | 21 +++++++++++++++++++++
 arch/x86/kvm/x86.h     |  5 +++++
 3 files changed, 28 insertions(+)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 4dc2459..2ebaa90 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6663,6 +6663,8 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
 	if (!vmx->vcpu.arch.core_cstate_msrs)
 		goto free_vmcs;
 
+	kvm_core_residency_setup(&vmx->vcpu);
+
 	if (nested)
 		nested_vmx_setup_ctls_msrs(&vmx->nested.msrs,
 					   vmx_capability.ept,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 841a794..36905cd 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1376,6 +1376,16 @@ void kvm_residency_write(struct kvm_vcpu *vcpu,
 }
 EXPORT_SYMBOL_GPL(kvm_residency_write);
 
+static void kvm_residency_setup(struct kvm_vcpu *vcpu, struct kvm_residency_msr *msr,
+		u16 index, bool count_with_host)
+{
+	/* Preserve value on calls after the first */
+	u64 value = msr->index ? kvm_residency_read(vcpu, msr->index) : 0;
+	msr->delta_from_host = msr->count_with_host = count_with_host;
+	msr->index = index;
+	kvm_residency_write(vcpu, msr->index, value);
+}
+
 /*
  * Writes msr value into into the appropriate "register".
  * Returns 0 on success, non-0 otherwise.
@@ -3311,6 +3321,17 @@ static bool need_emulate_wbinvd(struct kvm_vcpu *vcpu)
 	return kvm_arch_has_noncoherent_dma(vcpu->kvm);
 }
 
+void kvm_core_residency_setup(struct kvm_vcpu *vcpu)
+{
+	kvm_residency_setup(vcpu, &vcpu->arch.core_cstate_msrs[0],
+		MSR_CORE_C3_RESIDENCY, kvm_mwait_in_guest(vcpu->kvm));
+	kvm_residency_setup(vcpu, &vcpu->arch.core_cstate_msrs[1],
+		MSR_CORE_C6_RESIDENCY, kvm_mwait_in_guest(vcpu->kvm));
+	kvm_residency_setup(vcpu, &vcpu->arch.core_cstate_msrs[2],
+		MSR_CORE_C7_RESIDENCY, kvm_mwait_in_guest(vcpu->kvm));
+}
+EXPORT_SYMBOL_GPL(kvm_core_residency_setup);
+
 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 {
 	/* Address WBINVD may be executed by guest */
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index dc61dbd..123fc8d 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -284,6 +284,11 @@ bool kvm_vector_hashing_enabled(void);
 int x86_emulate_instruction(struct kvm_vcpu *vcpu, unsigned long cr2,
 			    int emulation_type, void *insn, int insn_len);
 
+u64 kvm_residency_read(struct kvm_vcpu *vcpu, u32 msr_index);
+void kvm_residency_write(struct kvm_vcpu *vcpu,
+				u32 msr_index, u64 value);
+void kvm_core_residency_setup(struct kvm_vcpu *vcpu);
+
 #define KVM_SUPPORTED_XCR0     (XFEATURE_MASK_FP | XFEATURE_MASK_SSE \
 				| XFEATURE_MASK_YMM | XFEATURE_MASK_BNDREGS \
 				| XFEATURE_MASK_BNDCSR | XFEATURE_MASK_AVX512 \
-- 
2.7.4