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[Qemu-devel] [PULL 10/12] target-i386: Reorganize TSC rate setting code
From: |
Eduardo Habkost |
Subject: |
[Qemu-devel] [PULL 10/12] target-i386: Reorganize TSC rate setting code |
Date: |
Thu, 21 Jan 2016 13:09:39 -0200 |
From: Haozhong Zhang <address@hidden>
Following 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 kvm_arch_set_tsc_khz() fails, i.e. following two conditions are
both satisfied:
* KVM does not support the TSC scaling or it fails to set vcpu's
TSC rate by KVM_SET_TSC_KHZ,
* the TSC rate to be set is different than the value currently used
by KVM, then kvm_arch_init_vcpu() will fail. Prevously,
* the lack of TSC scaling never failed kvm_arch_init_vcpu(),
* the failure of KVM_SET_TSC_KHZ failed kvm_arch_init_vcpu()
unconditionally, even though the TSC rate to be set is identical
to the value currently used by KVM.
Signed-off-by: Haozhong Zhang <address@hidden>
Reviewed-by: Eduardo Habkost <address@hidden>
Signed-off-by: Eduardo Habkost <address@hidden>
---
target-i386/kvm.c | 40 +++++++++++++++++++++++++++++++++-------
1 file changed, 33 insertions(+), 7 deletions(-)
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 1212b50..23d6b86 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -532,6 +532,36 @@ static bool hyperv_enabled(X86CPU *cpu)
cpu->hyperv_stimer);
}
+static int kvm_arch_set_tsc_khz(CPUState *cs)
+{
+ X86CPU *cpu = X86_CPU(cs);
+ CPUX86State *env = &cpu->env;
+ int r;
+
+ if (!env->tsc_khz) {
+ return 0;
+ }
+
+ r = kvm_check_extension(cs->kvm_state, KVM_CAP_TSC_CONTROL) ?
+ kvm_vcpu_ioctl(cs, KVM_SET_TSC_KHZ, env->tsc_khz) :
+ -ENOTSUP;
+ if (r < 0) {
+ /* When KVM_SET_TSC_KHZ fails, it's an error only if the current
+ * TSC frequency doesn't match the one we want.
+ */
+ int cur_freq = kvm_check_extension(cs->kvm_state, KVM_CAP_GET_TSC_KHZ)
?
+ kvm_vcpu_ioctl(cs, KVM_GET_TSC_KHZ) :
+ -ENOTSUP;
+ if (cur_freq <= 0 || cur_freq != env->tsc_khz) {
+ error_report("warning: TSC frequency mismatch between "
+ "VM and host, and TSC scaling unavailable");
+ return r;
+ }
+ }
+
+ return 0;
+}
+
static Error *invtsc_mig_blocker;
#define KVM_MAX_CPUID_ENTRIES 100
@@ -859,13 +889,9 @@ 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;
- }
+ r = kvm_arch_set_tsc_khz(cs);
+ if (r < 0) {
+ return r;
}
/* vcpu's TSC frequency is either specified by user, or following
--
2.1.0
- [Qemu-devel] [PULL 00/12] X86 queue, 2016-01-21, Eduardo Habkost, 2016/01/21
- [Qemu-devel] [PULL 01/12] target-i386: Rename optimize_flags_init(), Eduardo Habkost, 2016/01/21
- [Qemu-devel] [PULL 03/12] target-i386: Use a _q array on MMXReg too, Eduardo Habkost, 2016/01/21
- [Qemu-devel] [PULL 02/12] target-i386/ops_sse.h: Use MMX_Q macro, Eduardo Habkost, 2016/01/21
- [Qemu-devel] [PULL 07/12] target-i386: Define MMREG_UNION macro, Eduardo Habkost, 2016/01/21
- [Qemu-devel] [PULL 04/12] target-i386: Rename struct XMMReg to ZMMReg, Eduardo Habkost, 2016/01/21
- [Qemu-devel] [PULL 08/12] target-i386: Add suffixes to MMReg struct fields, Eduardo Habkost, 2016/01/21
- [Qemu-devel] [PULL 06/12] target-i386: Define MMXReg._d field, Eduardo Habkost, 2016/01/21
- [Qemu-devel] [PULL 09/12] target-i386: Fallback vcpu's TSC rate to value returned by KVM, Eduardo Habkost, 2016/01/21
- [Qemu-devel] [PULL 05/12] target-i386: Rename XMM_[BWLSDQ] helpers to ZMM_*, Eduardo Habkost, 2016/01/21
- [Qemu-devel] [PULL 10/12] target-i386: Reorganize TSC rate setting code,
Eduardo Habkost <=
- [Qemu-devel] [PULL 11/12] target-i386: Add support to migrate vcpu's TSC rate, Eduardo Habkost, 2016/01/21
- [Qemu-devel] [PULL 12/12] target-i386: Add PKU and and OSPKE support, Eduardo Habkost, 2016/01/21
- Re: [Qemu-devel] [PULL 00/12] X86 queue, 2016-01-21, Peter Maydell, 2016/01/21