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[Qemu-devel] [PATCH v5 2/3] target-i386: reorganize TSC rate setting cod
From: |
Haozhong Zhang |
Subject: |
[Qemu-devel] [PATCH v5 2/3] target-i386: reorganize TSC rate setting code |
Date: |
Tue, 17 Nov 2015 13:20:38 +0800 |
Following two changes are made to the TSC rate setting code in
kvm_arch_init_vcpu():
* The code is moved to a new function kvm_arch_set_tsc_khz().
* If setting user-specified TSC rate fails and the host TSC rate is
inconsistent with the user-specified one, print a warning message.
Signed-off-by: Haozhong Zhang <address@hidden>
---
target-i386/kvm.c | 45 ++++++++++++++++++++++++++++++++++++++-------
1 file changed, 38 insertions(+), 7 deletions(-)
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 9e4d27f..6a1acb4 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -524,6 +524,41 @@ static bool hyperv_enabled(X86CPU *cpu)
cpu->hyperv_runtime);
}
+/**
+ * Ask KVM to set vcpu's TSC rate to X86_CPU(cs)->env.tsc_khz.
+ *
+ * Returns: 0 if successful;
+ * -ENOTSUP if KVM_CAP_TSC_CONTROL is unavailable;
+ * -EIO if KVM_SET_TSC_KHZ fails.
+ */
+static int kvm_arch_set_tsc_khz(CPUState *cs)
+{
+ X86CPU *cpu = X86_CPU(cs);
+ CPUX86State *env = &cpu->env;
+ int has_tsc_control, r = 0;
+
+ if (!env->tsc_khz) {
+ return 0;
+ }
+
+ has_tsc_control = kvm_check_extension(cs->kvm_state, KVM_CAP_TSC_CONTROL);
+ if (has_tsc_control) {
+ r = kvm_vcpu_ioctl(cs, KVM_SET_TSC_KHZ, env->tsc_khz);
+ }
+
+ if (!has_tsc_control || r < 0) {
+ r = kvm_check_extension(cs->kvm_state, KVM_CAP_GET_TSC_KHZ) ?
+ kvm_vcpu_ioctl(cs, KVM_GET_TSC_KHZ) : -ENOTSUP;
+ if (r <= 0 || r != env->tsc_khz) {
+ error_report("warning: TSC frequency mismatch between "
+ "VM and host, and TSC scaling unavailable");
+ return has_tsc_control ? -EIO : -ENOTSUP;
+ }
+ }
+
+ return 0;
+}
+
static Error *invtsc_mig_blocker;
#define KVM_MAX_CPUID_ENTRIES 100
@@ -823,13 +858,9 @@ int kvm_arch_init_vcpu(CPUState *cs)
return r;
}
- r = kvm_check_extension(cs->kvm_state, KVM_CAP_TSC_CONTROL);
- if (r && env->tsc_khz) {
- r = kvm_vcpu_ioctl(cs, KVM_SET_TSC_KHZ, env->tsc_khz);
- if (r < 0) {
- fprintf(stderr, "KVM_SET_TSC_KHZ failed\n");
- return r;
- }
+ if (kvm_arch_set_tsc_khz(cs) == -EIO) {
+ fprintf(stderr, "KVM_SET_TSC_KHZ failed\n");
+ return -EIO;
}
/*
--
2.4.8