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e4aa7f88af
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Chao Gao e4aa7f88af KVM: Disable CPU hotplug during hardware enabling/disabling 
Disable CPU hotplug when enabling/disabling hardware to prevent the
corner case where if the following sequence occurs:

  1. A hotplugged CPU marks itself online in cpu_online_mask
  2. The hotplugged CPU enables interrupt before invoking KVM's ONLINE
     callback
  3  hardware_{en,dis}able_all() is invoked on another CPU

the hotplugged CPU will be included in on_each_cpu() and thus get sent
through hardware_{en,dis}able_nolock() before kvm_online_cpu() is called.

        start_secondary { ...
                set_cpu_online(smp_processor_id(), true); <- 1
                ...
                local_irq_enable();  <- 2
                ...
                cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); <- 3
        }

KVM currently fudges around this race by keeping track of which CPUs have
done hardware enabling (see commit 1b6c016818 "KVM: Keep track of which
cpus have virtualization enabled"), but that's an inefficient, convoluted,
and hacky solution.

Signed-off-by: Chao Gao <chao.gao@intel.com>
[sean: split to separate patch, write changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221130230934.1014142-43-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-29 15:48:32 -05:00
..
alpha MM patches for 6.2-rc1. 2022-12-13 19:29:45 -08:00
arc MM patches for 6.2-rc1. 2022-12-13 19:29:45 -08:00
arm ARM: SoC fixes for 6.2 2022-12-19 16:07:59 -06:00
arm64 KVM: x86: Unify pr_fmt to use module name for all KVM modules 2022-12-29 15:47:35 -05:00
csky arch/csky patches for 6.2-rc1 2022-12-19 07:51:30 -06:00
hexagon MM patches for 6.2-rc1. 2022-12-13 19:29:45 -08:00
ia64 - Add the call depth tracking mitigation for Retbleed which has 2022-12-14 15:03:00 -08:00
loongarch LoongArch changes for v6.2 2022-12-19 08:23:27 -06:00
m68k m68k: remove broken strcmp implementation 2022-12-21 08:56:43 -08:00
microblaze MM patches for 6.2-rc1. 2022-12-13 19:29:45 -08:00
mips KVM: Drop kvm_arch_check_processor_compat() hook 2022-12-29 15:41:28 -05:00
nios2 MM patches for 6.2-rc1. 2022-12-13 19:29:45 -08:00
openrisc MM patches for 6.2-rc1. 2022-12-13 19:29:45 -08:00
parisc parisc architecture fixes for kernel v6.2-rc1: 2022-12-20 08:43:53 -06:00
powerpc KVM: Drop kvm_arch_check_processor_compat() hook 2022-12-29 15:41:28 -05:00
riscv KVM: Drop kvm_arch_check_processor_compat() hook 2022-12-29 15:41:28 -05:00
s390 KVM: Drop kvm_arch_check_processor_compat() hook 2022-12-29 15:41:28 -05:00
sh treewide: Convert del_timer*() to timer_shutdown*() 2022-12-25 13:38:09 -08:00
sparc MM patches for 6.2-rc1. 2022-12-13 19:29:45 -08:00
um New Feature: 2022-12-17 14:06:53 -06:00
x86 KVM: Disable CPU hotplug during hardware enabling/disabling 2022-12-29 15:48:32 -05:00
xtensa MM patches for 6.2-rc1. 2022-12-13 19:29:45 -08:00
.gitignore
Kconfig arm64 fixes for -rc1 2022-12-16 13:46:41 -06:00