Sean Christopherson 37d2588185 KVM: Use a per-CPU variable to track which CPUs have enabled virtualization ... Use a per-CPU variable instead of a shared bitmap to track which CPUs have successfully enabled virtualization hardware. Using a per-CPU bool avoids the need for an additional allocation, and arguably yields easier to read code. Using a bitmap would be advantageous if KVM used it to avoid generating IPIs to CPUs that failed to enable hardware, but that's an extreme edge case and not worth optimizing, and the low level helpers would still want to keep their individual checks as attempting to enable virtualization hardware when it's already enabled can be problematic, e.g. Intel's VMXON will fault. Opportunistically change the order in hardware_enable_nolock() to set the flag if and only if hardware enabling is successful, instead of speculatively setting the flag and then clearing it on failure. Add a comment explaining that the check in hardware_disable_nolock() isn't simply paranoia. Waaay back when, commit 1b6c016818 ("KVM: Keep track of which cpus have virtualization enabled"), added the logic as a guards against CPU hotplug racing with hardware enable/disable. Now that KVM has eliminated the race by taking cpu_hotplug_lock for read (via cpus_read_lock()) when enabling or disabling hardware, at first glance it appears that the check is now superfluous, i.e. it's tempting to remove the per-CPU flag entirely... Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-47-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>		2022-12-29 15:48:35 -05:00
..
async_pf.c	KVM: Add helpers to wake/query blocking vCPU	2021-12-08 04:24:54 -05:00
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: mmio: Fix use-after-free Read in kvm_vm_ioctl_unregister_coalesced_mmio	2021-07-14 12:17:56 -04:00
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: Support dirty ring in conjunction with bitmap	2022-11-10 13:11:58 +00:00
eventfd.c	KVM: eventfd: Fix false positive RCU usage warning	2022-05-20 09:10:33 -04:00
irqchip.c	KVM: replace direct irq.h inclusion	2022-11-09 12:31:37 -05:00
Kconfig	KVM: Support dirty ring in conjunction with bitmap	2022-11-10 13:11:58 +00:00
kvm_main.c	KVM: Use a per-CPU variable to track which CPUs have enabled virtualization	2022-12-29 15:48:35 -05:00
kvm_mm.h	kvm: Remove the unused macro KVM_MMU_READ_{,UN}LOCK()	2022-12-27 06:00:51 -05:00
Makefile.kvm	KVM: Reinstate gfn_to_pfn_cache with invalidation support	2022-01-07 10:44:44 -05:00
pfncache.c	KVM: Skip unnecessary "unmap" if gpc is already valid during refresh	2022-11-30 19:25:24 +00:00
vfio.c	vfio: Hold a reference to the iommu_group in kvm for SPAPR	2022-10-07 08:10:52 -06:00
vfio.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00