KVM: VMX: hyper-v: Prevent impossible NULL pointer dereference in evmcs_load()

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GCC 12.3.0 complains about a potential NULL pointer dereference in
evmcs_load() as hv_get_vp_assist_page() can return NULL. In fact, this
cannot happen because KVM verifies (hv_init_evmcs()) that every CPU has a
valid VP assist page and aborts enabling the feature otherwise. CPU
onlining path is also checked in vmx_hardware_enable().

To make the compiler happy and to future proof the code, add a KVM_BUG_ON()
sentinel. It doesn't seem to be possible (and logical) to observe
evmcs_load() happening without an active vCPU so it is presumed that
kvm_get_running_vcpu() can't return NULL.

No functional change intended.

Reported-by: Mirsad Todorovac <mtodorovac69@gmail.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20240816130124.286226-1-vkuznets@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

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Vitaly Kuznetsov 2024-08-16 15:01:24 +02:00 • committed by Sean Christopherson

parent 41ab0d59fa

commit 2ab637df5f

1 changed files with 8 additions and 0 deletions

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arch/x86/kvm/vmx/vmx_onhyperv.h

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