----- pbonzini@xxxxxxxxxx wrote:
> Results on Haswell:
>
> wr_ibrs_msr 506 (actually ~250, because the test writes twice)
> wr_ibpb_msr 4212
>
> Yuck.
>
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> lib/x86/msr.h | 3 +++
> x86/vmexit.c | 23 +++++++++++++++++++++++
> 2 files changed, 26 insertions(+)
>
> diff --git a/lib/x86/msr.h b/lib/x86/msr.h
> index 2c0598c..3eff710 100644
> --- a/lib/x86/msr.h
> +++ b/lib/x86/msr.h
> @@ -32,6 +32,9 @@
> #define EFER_FFXSR (1<<_EFER_FFXSR)
>
> /* Intel MSRs. Some also available on other CPUs */
> +#define MSR_IA32_SPEC_CTRL 0x00000048
> +#define MSR_IA32_PRED_CMD 0x00000049
> +
> #define MSR_IA32_PERFCTR0 0x000000c1
> #define MSR_IA32_PERFCTR1 0x000000c2
> #define MSR_FSB_FREQ 0x000000cd
> diff --git a/x86/vmexit.c b/x86/vmexit.c
> index 65111ae..a04e971 100644
> --- a/x86/vmexit.c
> +++ b/x86/vmexit.c
> @@ -413,6 +413,27 @@ static void tscdeadline(void)
> while (x == 0) barrier();
> }
>
> +static int has_spec_ctrl(void)
> +{
> + return !!(cpuid_indexed(7,0).d & (1 << 26));
> +}
> +
> +static void wr_ibrs_msr(void)
> +{
> + wrmsr(MSR_IA32_SPEC_CTRL, 1);
> + wrmsr(MSR_IA32_SPEC_CTRL, 0);
> +}
> +
> +static int has_ibpb(void)
> +{
> + return has_spec_ctrl() || !!(cpuid(0x80000008).b & (1 << 12));
Why are you doing here "has_spec_ctrl() ||" and not just checking "cpuid(0x80000008).b & (1 << 12)"?
-Liran
> +}
> +
> +static void wr_ibpb_msr(void)
> +{
> + wrmsr(MSR_IA32_PRED_CMD, 1);
> +}
> +
> static struct test tests[] = {
> { cpuid_test, "cpuid", .parallel = 1, },
> { vmcall, "vmcall", .parallel = 1, },
> @@ -440,6 +461,8 @@ static struct test tests[] = {
> { ipi, "ipi", is_smp, .parallel = 0, },
> { ipi_halt, "ipi_halt", is_smp, .parallel = 0, },
> { ple_round_robin, "ple_round_robin", .parallel = 1 },
> + { wr_ibrs_msr, "wr_ibrs_msr", has_spec_ctrl, .parallel = 1 },
> + { wr_ibpb_msr, "wr_ibpb_msr", has_ibpb, .parallel = 1 },
> { wr_tsc_adjust_msr, "wr_tsc_adjust_msr", .parallel = 1 },
> { rd_tsc_adjust_msr, "rd_tsc_adjust_msr", .parallel = 1 },
> { NULL, "pci-mem", .parallel = 0, .next = pci_mem_next },
> --
> 1.8.3.1
