[PATCH 4/4] mshv: Add SMT_ENABLED_GUEST partition creation flag

[Anatol Belski <anbelski@linux.microsoft.com>]

Add support for HV_PARTITION_CREATION_FLAG_SMT_ENABLED_GUEST
to allow userspace VMMs to enable SMT for guest partitions.

Expose this via new MSHV_PT_BIT_SMT_ENABLED_GUEST flag in the UAPI.

Withouth this flag, the hypervisor schedules guest VPs incorrectly,
causing SMT unusable.

Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
---
 drivers/hv/mshv_root_main.c | 2 ++
 include/hyperv/hvhdk.h      | 1 +
 include/uapi/linux/mshv.h   | 1 +
 3 files changed, 4 insertions(+)

diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
index fb3ade44e1f1..899e055d975f 100644
--- a/drivers/hv/mshv_root_main.c
+++ b/drivers/hv/mshv_root_main.c
@@ -1923,6 +1923,8 @@ static long mshv_ioctl_process_pt_flags(void __user *user_arg, u64 *pt_flags,
 		*pt_flags |= HV_PARTITION_CREATION_FLAG_GPA_SUPER_PAGES_ENABLED;
 	if (args.pt_flags & BIT(MSHV_PT_BIT_NESTED_VIRTUALIZATION))
 		*pt_flags |= HV_PARTITION_CREATION_FLAG_NESTED_VIRTUALIZATION_CAPABLE;
+	if (args.pt_flags & BIT(MSHV_PT_BIT_SMT_ENABLED_GUEST))
+		*pt_flags |= HV_PARTITION_CREATION_FLAG_SMT_ENABLED_GUEST;
 
 	isol_props->as_uint64 = 0;
 
diff --git a/include/hyperv/hvhdk.h b/include/hyperv/hvhdk.h
index 03afb7d0412b..331cebc471e1 100644
--- a/include/hyperv/hvhdk.h
+++ b/include/hyperv/hvhdk.h
@@ -328,6 +328,7 @@ union hv_partition_isolation_properties {
 #define HV_PARTITION_ISOLATION_HOST_TYPE_RESERVED   0x2
 
 /* Note: Exo partition is enabled by default */
+#define HV_PARTITION_CREATION_FLAG_SMT_ENABLED_GUEST			BIT(0)
 #define HV_PARTITION_CREATION_FLAG_NESTED_VIRTUALIZATION_CAPABLE	BIT(1)
 #define HV_PARTITION_CREATION_FLAG_GPA_SUPER_PAGES_ENABLED		BIT(4)
 #define HV_PARTITION_CREATION_FLAG_EXO_PARTITION			BIT(8)
diff --git a/include/uapi/linux/mshv.h b/include/uapi/linux/mshv.h
index 7ef5dd67a232..e0645a34b55b 100644
--- a/include/uapi/linux/mshv.h
+++ b/include/uapi/linux/mshv.h
@@ -28,6 +28,7 @@ enum {
 	MSHV_PT_BIT_GPA_SUPER_PAGES,
 	MSHV_PT_BIT_CPU_AND_XSAVE_FEATURES,
 	MSHV_PT_BIT_NESTED_VIRTUALIZATION,
+	MSHV_PT_BIT_SMT_ENABLED_GUEST,
 	MSHV_PT_BIT_COUNT,
 };
 
-- 
2.34.1