x86/entry: KVM: Use dedicated VMX NMI entry for 32-bit kernels too

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Use a dedicated entry for invoking the NMI handler from KVM VMX's VM-Exit
path for 32-bit even though using a dedicated entry for 32-bit isn't
strictly necessary.  Exposing a single symbol will allow KVM to reference
the entry point in assembly code without having to resort to more #ifdefs
(or #defines).  identry.h is intended to be included from asm files only
once, and so simply including idtentry.h in KVM assembly isn't an option.

Bypassing the ESP fixup and CR3 switching in the standard NMI entry code
is safe as KVM always handles NMIs that occur in the guest on a kernel
stack, with a kernel CR3.

Cc: Andy Lutomirski <luto@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221213060912.654668-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

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This commit is contained in:

Sean Christopherson 2022-12-13 06:09:10 +00:00

parent 432727f1cb

commit 54a3b70a75

3 changed files with 12 additions and 16 deletions

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16

arch/x86/include/asm/idtentry.h

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8

arch/x86/kernel/nmi.c

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4

arch/x86/kvm/vmx/vmx.c

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