KVM: SEV: Do cache maintenance on the source VM during intra-host migrationgrafted

Manually perform cache maintenance on the source VM during intra-host
migration to ensure no stale data is left in CPU caches after the VM is
destroyed.  Because the source VM is "converted" to a non-SEV VM, KVM's
memory reclaim flows won't trigger cache maintenance, e.g. when all guest
memory is reclaimed in response to detaching from the mmu_notifier.

Note, relying on the destination VM to do cache maintenance isn't an option
as KVM doesn't require identical guest memory configurations, i.e. the
source VM may have access to memory that the destination VM does not.
Enforcing equivalent memory configurations is infeasible, as it would
require a *deep* comparison of memslots, e.g. to verify that not only are
the memslot identical, but what the memslots point at is also identical.

Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration")
Cc: stable@vger.kernel.org
Reported-by: Stefan Teodorescu <fane@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260923163721.1584779-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/amdpmf-interface b/Documentation/ABI/testing/amdpmf-interface
new file mode 100644
index 000000000..625f90a01
--- /dev/null
+++ b/Documentation/ABI/testing/amdpmf-interface
@@ -0,0 +1,73 @@
+What:		/dev/amdpmf_interface
+Date:		June 2026
+KernelVersion:	7.2
+Contact:	Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
+Description:
+		The AMD Platform Management Framework (PMF) util layer exposes a
+		minimal user-space interface via a character device for feature
+		discovery and metrics monitoring.
+
+		When CONFIG_AMD_PMF_UTIL_SUPPORT is enabled, the driver creates
+		a character device:
+
+		======================
+		/dev/amdpmf_interface
+		======================
+
+		The interface supports a single ioctl:
+
+		============================ =======================================
+		IOCTL			     Usage
+		IOCTL_AMD_PMF_POPULATE_DATA  User passes a struct amd_pmf_info with
+					     the size field set to sizeof(struct
+					     amd_pmf_info). The driver returns all
+					     available metrics and feature status
+					     in the structure.
+		============================ =======================================
+
+		struct amd_pmf_info layout:
+
+		======================= ========== ================================
+		Field			Type	   Description
+		size			__u64	   Structure size for versioning
+		features_supported	__u32	   Bitmask of supported features
+		platform_type		__u32	   Platform form factor orientation
+		power_source		__u32	   AC/DC power source
+		laptop_placement	__u32	   Device placement state
+		lid_state		__u32	   Lid open/closed status
+		user_presence		__u32	   User presence detection
+		slider_position		__u32	   Current power slider position
+		skin_temp		__s32	   Skin temperature (centidegrees)
+		gfx_busy		__u32	   Graphics workload percentage
+		ambient_light		__s32	   Ambient light sensor reading
+		avg_c0_residency	__u32	   Average C0 state residency
+		max_c0_residency	__u32	   Maximum C0 state residency
+		socket_power		__u32	   Socket power consumption
+		bios_input[10]		__u32	   Custom BIOS input parameters
+		bios_output[10]		__u32	   Custom BIOS output parameters
+		======================= ========== ================================
+
+		Feature Support Flags (features_supported bitmask):
+
+		=====================================    ====  =============================
+		Flag				         Bit   Description
+		AMD_PMF_FEAT_AUTO_MODE		         0     Auto Mode feature support
+		AMD_PMF_FEAT_STATIC_POWER_SLIDER         1     Static Power Slider support
+		AMD_PMF_FEAT_POLICY_BUILDER	         2     Policy Builder (Smart PC)
+		AMD_PMF_FEAT_DYNAMIC_POWER_SLIDER_AC     3     Dynamic slider on AC
+		AMD_PMF_FEAT_DYNAMIC_POWER_SLIDER_DC     4     Dynamic slider on DC
+		=====================================    ====  =============================
+
+		Return codes:
+
+		============= ============================================================
+		Return code   Description
+		0	      Success
+		EINVAL	      Invalid size or parameter
+		EFAULT	      copy_to_user/copy_from_user failures
+		ENODEV	      PMF device not available
+		ENOTTY	      Unknown ioctl command
+		============= ============================================================
+
+		User-space tools integrating with AMD PMF to discover capabilities and
+		monitor real-time metrics for thermal and power management validation.