David Matlack 1189645629 KVM: Mark a vCPU as preempted/ready iff it's scheduled out while running ... Mark a vCPU as preempted/ready if-and-only-if it's scheduled out while running. i.e. Do not mark a vCPU preempted/ready if it's scheduled out during a non-KVM_RUN ioctl() or when userspace is doing KVM_RUN with immediate_exit. Commit 54aa83c901 ("KVM: x86: do not set st->preempted when going back to user space") stopped marking a vCPU as preempted when returning to userspace, but if userspace then invokes a KVM vCPU ioctl() that gets preempted, the vCPU will be marked preempted/ready. This is arguably incorrect behavior since the vCPU was not actually preempted while the guest was running, it was preempted while doing something on behalf of userspace. Marking a vCPU preempted iff its running also avoids KVM dirtying guest memory after userspace has paused vCPUs, e.g. for live migration, which allows userspace to collect the final dirty bitmap before or in parallel with saving vCPU state, without having to worry about saving vCPU state triggering writes to guest memory. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Matlack <dmatlack@google.com> Link: https://lore.kernel.org/r/20240503181734.1467938-4-dmatlack@google.com [sean: massage changelog] Signed-off-by: Sean Christopherson <seanjc@google.com>		2024-06-18 09:22:42 -07:00
..
async_pf.c	Revert "KVM: async_pf: avoid recursive flushing of work items"	2024-06-03 08:55:55 -07:00
async_pf.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504	2019-06-19 17:09:56 +02:00
binary_stats.c	KVM: stats: remove dead stores	2021-08-13 03:35:15 -04:00
coalesced_mmio.c	KVM: destruct kvm_io_device while unregistering it from kvm_io_bus	2023-06-13 14:18:09 -07:00
coalesced_mmio.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
dirty_ring.c	KVM: Allow arch code to track number of memslot address spaces per VM	2023-11-14 08:01:05 -05:00
eventfd.c	Generic:	2024-01-17 13:03:37 -08:00
guest_memfd.c	Generic:	2024-01-17 13:03:37 -08:00
irqchip.c	KVM: Setup empty IRQ routing when creating a VM	2024-06-11 14:18:34 -07:00
Kconfig	Merge branch 'kvm-kconfig'	2024-02-08 08:47:51 -05:00
kvm_main.c	KVM: Mark a vCPU as preempted/ready iff it's scheduled out while running	2024-06-18 09:22:42 -07:00
kvm_mm.h	KVM: Drop unused @may_block param from gfn_to_pfn_cache_invalidate_start()	2024-04-11 12:58:53 -07:00
Makefile.kvm	KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory	2023-11-14 08:01:03 -05:00
pfncache.c	KVM: Drop unused @may_block param from gfn_to_pfn_cache_invalidate_start()	2024-04-11 12:58:53 -07:00
vfio.c	KVM: Treat the device list as an rculist	2024-04-25 13:19:55 +01:00
vfio.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00