diff options
Diffstat (limited to 'sys/amd64/vmm/x86.c')
| -rw-r--r-- | sys/amd64/vmm/x86.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/sys/amd64/vmm/x86.c b/sys/amd64/vmm/x86.c index 13eaaad..fa2eabc 100644 --- a/sys/amd64/vmm/x86.c +++ b/sys/amd64/vmm/x86.c @@ -34,6 +34,7 @@ __FBSDID("$FreeBSD$"); #include <sys/systm.h> #include <sys/cpuset.h> +#include <machine/clock.h> #include <machine/cpufunc.h> #include <machine/md_var.h> #include <machine/specialreg.h> @@ -89,11 +90,27 @@ x86_emulate_cpuid(struct vm *vm, int vcpu_id, case CPUID_8000_0003: case CPUID_8000_0004: case CPUID_8000_0006: - case CPUID_8000_0007: case CPUID_8000_0008: cpuid_count(*eax, *ecx, regs); break; + case CPUID_8000_0007: + cpuid_count(*eax, *ecx, regs); + /* + * If the host TSCs are not synchronized across + * physical cpus then we cannot advertise an + * invariant tsc to a vcpu. + * + * XXX This still falls short because the vcpu + * can observe the TSC moving backwards as it + * migrates across physical cpus. But at least + * it should discourage the guest from using the + * TSC to keep track of time. + */ + if (!smp_tsc) + regs[3] &= ~AMDPM_TSC_INVARIANT; + break; + case CPUID_0000_0001: do_cpuid(1, regs); |
