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, 192 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-netdev b/Documentation/ABI/testing/sysfs-class-led-trigger-netdev
new file mode 100644
index 000000000..ed46b37ab
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-trigger-netdev
@@ -0,0 +1,192 @@
+What:		/sys/class/leds/<led>/device_name
+Date:		Dec 2017
+KernelVersion:	4.16
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Specifies the network device name to monitor.
+
+What:		/sys/class/leds/<led>/interval
+Date:		Dec 2017
+KernelVersion:	4.16
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Specifies the duration of the LED blink in milliseconds.
+		Defaults to 50 ms.
+
+		When offloaded is true, the interval value MUST be set to the
+		default value and cannot be changed.
+		Trying to set any value in this specific mode will return
+		an EINVAL error.
+
+What:		/sys/class/leds/<led>/link
+Date:		Dec 2017
+KernelVersion:	4.16
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Signal the link state of the named network device.
+
+		If set to 0 (default), the LED's normal state is off.
+
+		If set to 1, the LED's normal state reflects the link state
+		of the named network device.
+		Setting this value also immediately changes the LED state.
+
+
+What:		/sys/class/leds/<led>/tx
+Date:		Dec 2017
+KernelVersion:	4.16
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Signal transmission of data on the named network device.
+
+		If set to 0 (default), the LED will not blink on transmission.
+
+		If set to 1, the LED will blink for the milliseconds specified
+		in interval to signal transmission.
+
+		When offloaded is true, the blink interval is controlled by
+		hardware and won't reflect the value set in interval.
+
+What:		/sys/class/leds/<led>/rx
+Date:		Dec 2017
+KernelVersion:	4.16
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Signal reception of data on the named network device.
+
+		If set to 0 (default), the LED will not blink on reception.
+
+		If set to 1, the LED will blink for the milliseconds specified
+		in interval to signal reception.
+
+		When offloaded is true, the blink interval is controlled by
+		hardware and won't reflect the value set in interval.
+
+What:		/sys/class/leds/<led>/offloaded
+Date:		Jun 2023
+KernelVersion:	6.5
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Communicate whether the LED trigger modes are offloaded to
+		hardware or whether software fallback is used.
+
+		If 0, the LED is using software fallback to blink.
+
+		If 1, the LED blinking in requested mode is offloaded to
+		hardware.
+
+What:		/sys/class/leds/<led>/link_10
+Date:		Jun 2023
+KernelVersion:	6.5
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Signal the link speed state of 10Mbps of the named network device.
+
+		If set to 0 (default), the LED's normal state is off.
+
+		If set to 1, the LED's normal state reflects the link state
+		speed of 10MBps of the named network device.
+		Setting this value also immediately changes the LED state.
+
+		Present only if the named network device supports 10Mbps link speed.
+
+What:		/sys/class/leds/<led>/link_100
+Date:		Jun 2023
+KernelVersion:	6.5
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Signal the link speed state of 100Mbps of the named network device.
+
+		If set to 0 (default), the LED's normal state is off.
+
+		If set to 1, the LED's normal state reflects the link state
+		speed of 100Mbps of the named network device.
+		Setting this value also immediately changes the LED state.
+
+		Present only if the named network device supports 100Mbps link speed.
+
+What:		/sys/class/leds/<led>/link_1000
+Date:		Jun 2023
+KernelVersion:	6.5
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Signal the link speed state of 1000Mbps of the named network device.
+
+		If set to 0 (default), the LED's normal state is off.
+
+		If set to 1, the LED's normal state reflects the link state
+		speed of 1000Mbps of the named network device.
+		Setting this value also immediately changes the LED state.
+
+		Present only if the named network device supports 1000Mbps link speed.
+
+What:		/sys/class/leds/<led>/link_2500
+Date:		Nov 2023
+KernelVersion:	6.8
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Signal the link speed state of 2500Mbps of the named network device.
+
+		If set to 0 (default), the LED's normal state is off.
+
+		If set to 1, the LED's normal state reflects the link state
+		speed of 2500Mbps of the named network device.
+		Setting this value also immediately changes the LED state.
+
+		Present only if the named network device supports 2500Mbps link speed.
+
+What:		/sys/class/leds/<led>/link_5000
+Date:		Nov 2023
+KernelVersion:	6.8
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Signal the link speed state of 5000Mbps of the named network device.
+
+		If set to 0 (default), the LED's normal state is off.
+
+		If set to 1, the LED's normal state reflects the link state
+		speed of 5000Mbps of the named network device.
+		Setting this value also immediately changes the LED state.
+
+		Present only if the named network device supports 5000Mbps link speed.
+
+What:		/sys/class/leds/<led>/link_10000
+Date:		Nov 2023
+KernelVersion:	6.8
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Signal the link speed state of 10000Mbps of the named network device.
+
+		If set to 0 (default), the LED's normal state is off.
+
+		If set to 1, the LED's normal state reflects the link state
+		speed of 10000Mbps of the named network device.
+		Setting this value also immediately changes the LED state.
+
+		Present only if the named network device supports 10000Mbps link speed.
+
+What:		/sys/class/leds/<led>/half_duplex
+Date:		Jun 2023
+KernelVersion:	6.5
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Signal the link half duplex state of the named network device.
+
+		If set to 0 (default), the LED's normal state is off.
+
+		If set to 1, the LED's normal state reflects the link half
+		duplex state of the named network device.
+		Setting this value also immediately changes the LED state.
+
+What:		/sys/class/leds/<led>/full_duplex
+Date:		Jun 2023
+KernelVersion:	6.5
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Signal the link full duplex state of the named network device.
+
+		If set to 0 (default), the LED's normal state is off.
+
+		If set to 1, the LED's normal state reflects the link full
+		duplex state of the named network device.
+		Setting this value also immediately changes the LED state.