[Patch v3 01/13] x86/hyperv: Add HV_EXPOSE_INVARIANT_TSC define

Vipin Sharma
2022-12-05T19:15:16Z

From: Vitaly Kuznetsov <vkuznets@redhat.com>

Avoid open coding BIT(0) of HV_X64_MSR_TSC_INVARIANT_CONTROL by adding
a dedicated define. While there's only one user at this moment, the
upcoming KVM implementation of Hyper-V Invariant TSC feature will need
to use it as well.

Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
arch/x86/include/asm/hyperv-tlfs.h | 3 +++
arch/x86/kernel/cpu/mshyperv.c | 2 +-
2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index e3efaf6e6b62..617332dd64ac 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -255,6 +255,9 @@ enum hv_isolation_type {
/* TSC invariant control */
#define HV_X64_MSR_TSC_INVARIANT_CONTROL 0x40000118

+/* HV_X64_MSR_TSC_INVARIANT_CONTROL bits */
+#define HV_EXPOSE_INVARIANT_TSC BIT_ULL(0)
+
/* Register name aliases for temporary compatibility */
#define HV_X64_MSR_STIMER0_COUNT HV_REGISTER_STIMER0_COUNT
#define HV_X64_MSR_STIMER0_CONFIG HV_REGISTER_STIMER0_CONFIG
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 831613959a92..e402923800d7 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -388,7 +388,7 @@ static void __init ms_hyperv_init_platform(void)
* setting of this MSR bit should happen before init_intel()
* is called.
*/
- wrmsrl(HV_X64_MSR_TSC_INVARIANT_CONTROL, 0x1);
+ wrmsrl(HV_X64_MSR_TSC_INVARIANT_CONTROL, HV_EXPOSE_INVARIANT_TSC);
setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);