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, 134 insertions, 0 deletions

diff --git a/Documentation/usb/chipidea.rst b/Documentation/usb/chipidea.rst
new file mode 100644
index 000000000..d9920c24e
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+++ b/Documentation/usb/chipidea.rst
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+==============================================
+ChipIdea Highspeed Dual Role Controller Driver
+==============================================
+
+1. How to test OTG FSM(HNP and SRP)
+-----------------------------------
+
+To show how to demo OTG HNP and SRP functions via sys input files
+with 2 Freescale i.MX6Q sabre SD boards.
+
+1.1 How to enable OTG FSM
+-------------------------
+
+1.1.1 Select CONFIG_USB_OTG_FSM in menuconfig, rebuild kernel
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Image and modules. If you want to check some internal
+variables for otg fsm, mount debugfs, there are 2 files
+which can show otg fsm variables and some controller registers value::
+
+	cat /sys/kernel/debug/ci_hdrc.0/otg
+	cat /sys/kernel/debug/ci_hdrc.0/registers
+
+1.1.2 Add below entries in your dts file for your controller node
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+::
+
+	otg-rev = <0x0200>;
+	adp-disable;
+
+1.2 Test operations
+-------------------
+
+1) Power up 2 Freescale i.MX6Q sabre SD boards with gadget class driver loaded
+   (e.g. g_mass_storage).
+
+2) Connect 2 boards with usb cable: one end is micro A plug, the other end
+   is micro B plug.
+
+   The A-device (with micro A plug inserted) should enumerate B-device.
+
+3) Role switch
+
+   On B-device::
+
+	echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req
+
+   B-device should take host role and enumerate A-device.
+
+4) A-device switch back to host.
+
+   On B-device::
+
+	echo 0 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req
+
+   or, by introducing HNP polling, B-Host can know when A-peripheral wishes to
+   be in the host role, so this role switch also can be triggered in
+   A-peripheral side by answering the polling from B-Host. This can be done on
+   A-device::
+
+	echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req
+
+   A-device should switch back to host and enumerate B-device.
+
+5) Remove B-device (unplug micro B plug) and insert again in 10 seconds;
+   A-device should enumerate B-device again.
+
+6) Remove B-device (unplug micro B plug) and insert again after 10 seconds;
+   A-device should NOT enumerate B-device.
+
+   if A-device wants to use bus:
+
+   On A-device::
+
+	echo 0 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_drop
+	echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req
+
+   if B-device wants to use bus:
+
+   On B-device::
+
+	echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req
+
+7) A-device power down the bus.
+
+   On A-device::
+
+	echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_drop
+
+   A-device should disconnect with B-device and power down the bus.
+
+8) B-device does data pulse for SRP.
+
+   On B-device::
+
+	echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req
+
+   A-device should resume usb bus and enumerate B-device.
+
+1.3 Reference document
+----------------------
+"On-The-Go and Embedded Host Supplement to the USB Revision 2.0 Specification
+July 27, 2012 Revision 2.0 version 1.1a"
+
+2. How to enable USB as system wakeup source
+--------------------------------------------
+Below is the example for how to enable USB as system wakeup source
+on an imx6 platform.
+
+2.1 Enable core's wakeup::
+
+	echo enabled > /sys/bus/platform/devices/ci_hdrc.0/power/wakeup
+
+2.2 Enable glue layer's wakeup::
+
+	echo enabled > /sys/bus/platform/devices/2184000.usb/power/wakeup
+
+2.3 Enable PHY's wakeup (optional)::
+
+	echo enabled > /sys/bus/platform/devices/20c9000.usbphy/power/wakeup
+
+2.4 Enable roothub's wakeup::
+
+	echo enabled > /sys/bus/usb/devices/usb1/power/wakeup
+
+2.5 Enable related device's wakeup::
+
+	echo enabled > /sys/bus/usb/devices/1-1/power/wakeup
+
+If the system has only one usb port, and you want usb wakeup at this port, you
+can use the below script to enable usb wakeup::
+
+	for i in $(find /sys -name wakeup | grep usb);do echo enabled > $i;done;