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Date: Wed, 9 Feb 2011 18:29:43 +0100
From: Joerg Roedel <joerg.roedel@....com>
To: Avi Kivity <avi@...hat.com>, Marcelo Tosatti <mtosatti@...hat.com>
CC: <kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
Zachary Amsden <zamsden@...hat.com>,
Joerg Roedel <joerg.roedel@....com>
Subject: [PATCH 5/6] KVM: X86: Delegate tsc-offset calculation to architecture code
With TSC scaling in SVM the tsc-offset needs to be
calculated differently. This patch propagates this
calculation into the architecture specific modules so that
this complexity can be handled there.
Signed-off-by: Joerg Roedel <joerg.roedel@....com>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/svm.c | 11 ++++++++++-
arch/x86/kvm/vmx.c | 6 ++++++
arch/x86/kvm/x86.c | 10 +++++-----
4 files changed, 22 insertions(+), 6 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 9686950..8c40425 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -593,6 +593,7 @@ struct kvm_x86_ops {
void (*write_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset);
bool (*use_virtual_tsc_khz)(struct kvm_vcpu *vcpu);
+ u64 (*compute_tsc_offset)(struct kvm_vcpu *vcpu, u64 target_tsc);
void (*get_exit_info)(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2);
const struct trace_print_flags *exit_reasons_str;
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 29833a7..f938585 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -881,7 +881,6 @@ static u64 svm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc)
static bool svm_vcpu_init_tsc(struct kvm *kvm, struct vcpu_svm *svm)
{
- u64 raw_tsc, tsc, new_tsc;
u64 ratio;
u64 khz;
@@ -941,6 +940,15 @@ static bool svm_use_virtual_tsc_khz(struct kvm_vcpu *vcpu)
return svm->tsc_scale.enabled;
}
+static u64 svm_compute_tsc_offset(struct kvm_vcpu *vcpu, u64 target_tsc)
+{
+ u64 tsc;
+
+ tsc = svm_scale_tsc(vcpu, native_read_tsc());
+
+ return target_tsc - tsc;
+}
+
static void init_vmcb(struct vcpu_svm *svm)
{
struct vmcb_control_area *control = &svm->vmcb->control;
@@ -4016,6 +4024,7 @@ static struct kvm_x86_ops svm_x86_ops = {
.write_tsc_offset = svm_write_tsc_offset,
.adjust_tsc_offset = svm_adjust_tsc_offset,
.use_virtual_tsc_khz = svm_use_virtual_tsc_khz,
+ .compute_tsc_offset = svm_compute_tsc_offset,
.set_tdp_cr3 = set_tdp_cr3,
};
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c227a6b..9bbdf1f 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1169,6 +1169,11 @@ static bool vmx_use_virtual_tsc_khz(struct kvm_vcpu *vcpu)
return false;
}
+static u64 vmx_compute_tsc_offset(struct kvm_vcpu *vcpu, u64 target_tsc)
+{
+ return target_tsc - native_read_tsc();
+}
+
/*
* Reads an msr value (of 'msr_index') into 'pdata'.
* Returns 0 on success, non-0 otherwise.
@@ -4449,6 +4454,7 @@ static struct kvm_x86_ops vmx_x86_ops = {
.write_tsc_offset = vmx_write_tsc_offset,
.adjust_tsc_offset = vmx_adjust_tsc_offset,
.use_virtual_tsc_khz = vmx_use_virtual_tsc_khz,
+ .compute_tsc_offset = vmx_compute_tsc_offset,
.set_tdp_cr3 = vmx_set_cr3,
};
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 597abc8..6caaf4b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -987,7 +987,7 @@ static u64 vcpu_tsc_khz(struct kvm_vcpu *vcpu)
return __this_cpu_read(cpu_tsc_khz);
}
-static inline u64 nsec_to_cycles(u64 nsec)
+static inline u64 nsec_to_cycles(struct kvm_vcpu *vcpu, u64 nsec)
{
u64 ret;
@@ -995,7 +995,7 @@ static inline u64 nsec_to_cycles(u64 nsec)
if (kvm_tsc_changes_freq())
printk_once(KERN_WARNING
"kvm: unreliable cycle conversion on adjustable rate TSC\n");
- ret = nsec * __this_cpu_read(cpu_tsc_khz);
+ ret = nsec * vcpu_tsc_khz(vcpu);
do_div(ret, USEC_PER_SEC);
return ret;
}
@@ -1027,7 +1027,7 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data)
s64 sdiff;
spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags);
- offset = data - native_read_tsc();
+ offset = kvm_x86_ops->compute_tsc_offset(vcpu, data);
ns = get_kernel_ns();
elapsed = ns - kvm->arch.last_tsc_nsec;
sdiff = data - kvm->arch.last_tsc_write;
@@ -1043,13 +1043,13 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data)
* In that case, for a reliable TSC, we can match TSC offsets,
* or make a best guest using elapsed value.
*/
- if (sdiff < nsec_to_cycles(5ULL * NSEC_PER_SEC) &&
+ if (sdiff < nsec_to_cycles(vcpu, 5ULL * NSEC_PER_SEC) &&
elapsed < 5ULL * NSEC_PER_SEC) {
if (!check_tsc_unstable()) {
offset = kvm->arch.last_tsc_offset;
pr_debug("kvm: matched tsc offset for %llu\n", data);
} else {
- u64 delta = nsec_to_cycles(elapsed);
+ u64 delta = nsec_to_cycles(vcpu, elapsed);
offset += delta;
pr_debug("kvm: adjusted tsc offset by %llu\n", delta);
}
--
1.7.1
--
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