KVM: SVM: Move GHCB unmapping to fix RCU warning

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When an SEV-ES guest is running, the GHCB is unmapped as part of the
vCPU run support. However, kvm_vcpu_unmap() triggers an RCU dereference
warning with CONFIG_PROVE_LOCKING=y because the SRCU lock is released
before invoking the vCPU run support.

Move the GHCB unmapping into the prepare_guest_switch callback, which is
invoked while still holding the SRCU lock, eliminating the RCU dereference
warning.

Fixes: 291bd20d5d ("KVM: SVM: Add initial support for a VMGEXIT VMEXIT")
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <b2f9b79d15166f2c3e4375c0d9bc3268b7696455.1620332081.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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This commit is contained in:

Tom Lendacky 2021-05-06 15:14:41 -05:00 • committed by Paolo Bonzini

parent 368340a3c7

commit ce7ea0cfdc

3 changed files with 5 additions and 4 deletions

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5

arch/x86/kvm/svm/sev.c

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3

arch/x86/kvm/svm/svm.c

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1

arch/x86/kvm/svm/svm.h

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