From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration 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 Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- Documentation/ABI/testing/rtc-cdev | 50 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 Documentation/ABI/testing/rtc-cdev (limited to 'Documentation/ABI/testing/rtc-cdev') diff --git a/Documentation/ABI/testing/rtc-cdev b/Documentation/ABI/testing/rtc-cdev new file mode 100644 index 000000000..cec099a27 --- /dev/null +++ b/Documentation/ABI/testing/rtc-cdev @@ -0,0 +1,50 @@ +What: /dev/rtcX +Date: April 2005 +KernelVersion: 2.6.12 +Contact: linux-rtc@vger.kernel.org +Description: + The ioctl interface to drivers for real-time clocks (RTCs). + Following actions are supported: + + * RTC_RD_TIME, RTC_SET_TIME: Read or set the RTC time. Time + format is a Gregorian calendar date and 24 hour wall clock + time. + + * RTC_AIE_ON, RTC_AIE_OFF: Enable or disable the alarm interrupt + for RTCs that support alarms + + * RTC_ALM_READ, RTC_ALM_SET: Read or set the alarm time for + RTCs that support alarms. Can be set up to 24 hours in the + future. Requires a separate RTC_AIE_ON call to enable the + alarm interrupt. (Prefer to use RTC_WKALM_*) + + * RTC_WKALM_RD, RTC_WKALM_SET: For RTCs that support a more + powerful interface, which can issue alarms beyond 24 hours and + enable IRQs in the same request. + + * RTC_PIE_ON, RTC_PIE_OFF: Enable or disable the periodic + interrupt for RTCs that support periodic interrupts. + + * RTC_UIE_ON, RTC_UIE_OFF: Enable or disable the update + interrupt for RTCs that support it. + + * RTC_IRQP_READ, RTC_IRQP_SET: Read or set the frequency for + periodic interrupts for RTCs that support periodic interrupts. + Requires a separate RTC_PIE_ON call to enable the periodic + interrupts. + + * RTC_VL_READ: Read the voltage inputs status of the RTC when + supported. The value is a bit field of RTC_VL_*, giving the + status of the main and backup voltages. + + * RTC_VL_CLEAR: Clear the voltage status of the RTC. Some RTCs + need user interaction when the backup power provider is + replaced or charged to be able to clear the status. + + The ioctl() calls supported by the older /dev/rtc interface are + also supported by the newer RTC class framework. However, + because the chips and systems are not standardized, some PC/AT + functionality might not be provided. And in the same way, some + newer features -- including those enabled by ACPI -- are exposed + by the RTC class framework, but can't be supported by the older + driver. -- cgit v1.3.1