mshv: Add SMT_ENABLED_GUEST partition creation flag

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.

Without this flag, the hypervisor schedules guest VPs incorrectly,
causing SMT unusable.

Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>

Author: weltling

drivers/hv/mshv_root_main.c

@@ -1949,6 +1949,8 @@ 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;
 

include/hyperv/hvhdk.h

@@ -335,6 +335,7 @@ 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)

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,
 };