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target-i386: Enabling IA32_TSC_ADJUST for QEMU KVM guest VMs

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CPUID.7.0.EBX[1]=1 indicates IA32_TSC_ADJUST MSR 0x3b is supported

Basic design is to emulate the MSR by allowing reads and writes to the
hypervisor vcpu specific locations to store the value of the emulated MSRs.
In this way the IA32_TSC_ADJUST value will be included in all reads to
the TSC MSR whether through rdmsr or rdtsc.

As this is a new MSR that the guest may access and modify its value needs
to be migrated along with the other MRSs. The changes here are specifically
for recognizing when IA32_TSC_ADJUST is enabled in CPUID and code added
for migrating its value.

Signed-off-by: Will Auld <will.auld@intel.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Will Auld 2012-11-26 21:32:18 -08:00 • committed by Marcelo Tosatti
parent e376a788ae
commit f28558d3d3
3 changed files with 37 additions and 0 deletions
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21
target-i386/machine.c
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@ -328,6 +328,24 @@ static const VMStateDescription vmstate_fpop_ip_dp = {
}
};
static bool tsc_adjust_needed(void *opaque)
{
CPUX86State *env = opaque;
return env->tsc_adjust != 0;
}
static const VMStateDescription vmstate_msr_tsc_adjust = {
.name = "cpu/msr_tsc_adjust",
.version_id = 1,
.minimum_version_id = 1,
.minimum_version_id_old = 1,
.fields = (VMStateField[]) {
VMSTATE_UINT64(tsc_adjust, CPUX86State),
VMSTATE_END_OF_LIST()
}
};
static bool tscdeadline_needed(void *opaque)
{
CPUX86State *env = opaque;
@ -477,6 +495,9 @@ static const VMStateDescription vmstate_cpu = {
} , {
.vmsd = &vmstate_fpop_ip_dp,
.needed = fpop_ip_dp_needed,
}, {
.vmsd = &vmstate_msr_tsc_adjust,
.needed = tsc_adjust_needed,
}, {
.vmsd = &vmstate_msr_tscdeadline,
.needed = tscdeadline_needed,