[PATCH 2/8] KVM: X86: Store L1's TSC scaling ratio in 'struct kvm_vcpu_arch'

[ilstam@mailbox.org]

From: Ilias Stamatis <ilstam@amazon.com>

Store L1's scaling ratio in that struct like we already do for L1's TSC
offset. This allows for easy save/restore when we enter and then exit
the nested guest.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>
---
 arch/x86/include/asm/kvm_host.h | 5 +++--
 arch/x86/kvm/x86.c              | 4 +++-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index cbbcee0a84f9..132e820525fb 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -705,7 +705,7 @@ struct kvm_vcpu_arch {
 	} st;
 
 	u64 l1_tsc_offset;
-	u64 tsc_offset;
+	u64 tsc_offset; /* current tsc offset */
 	u64 last_guest_tsc;
 	u64 last_host_tsc;
 	u64 tsc_offset_adjustment;
@@ -719,7 +719,8 @@ struct kvm_vcpu_arch {
 	u32 virtual_tsc_khz;
 	s64 ia32_tsc_adjust_msr;
 	u64 msr_ia32_power_ctl;
-	u64 tsc_scaling_ratio;
+	u64 l1_tsc_scaling_ratio;
+	u64 tsc_scaling_ratio; /* current scaling ratio */
 
 	atomic_t nmi_queued;  /* unprocessed asynchronous NMIs */
 	unsigned nmi_pending; /* NMI queued after currently running handler */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cebdaa1e3cf5..7bc5155ac6fd 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2119,6 +2119,7 @@ static int set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
 
 	/* Guest TSC same frequency as host TSC? */
 	if (!scale) {
+		vcpu->arch.l1_tsc_scaling_ratio = kvm_default_tsc_scaling_ratio;
 		vcpu->arch.tsc_scaling_ratio = kvm_default_tsc_scaling_ratio;
 		return 0;
 	}
@@ -2145,7 +2146,7 @@ static int set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
 		return -1;
 	}
 
-	vcpu->arch.tsc_scaling_ratio = ratio;
+	vcpu->arch.l1_tsc_scaling_ratio = vcpu->arch.tsc_scaling_ratio = ratio;
 	return 0;
 }
 
@@ -2157,6 +2158,7 @@ static int kvm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz)
 	/* tsc_khz can be zero if TSC calibration fails */
 	if (user_tsc_khz == 0) {
 		/* set tsc_scaling_ratio to a safe value */
+		vcpu->arch.l1_tsc_scaling_ratio = kvm_default_tsc_scaling_ratio;
 		vcpu->arch.tsc_scaling_ratio = kvm_default_tsc_scaling_ratio;
 		return -1;
 	}
-- 
2.17.1