Sean Christopherson 1ce072cbfd KVM: nVMX: Check a single byte for VMCS "launched" in nested early checks ... Nested early checks does a manual comparison of a VMCS' launched status in its asm blob to execute the correct VM-Enter instruction, i.e. VMLAUNCH vs. VMRESUME. The launched flag is a bool, which is a typedef of _Bool. C99 does not define an exact size for _Bool, stating only that is must be large enough to hold '0' and '1'. Most, if not all, compilers use a single byte for _Bool, including gcc[1]. The use of 'cmpl' instead of 'cmpb' was not deliberate, but rather the result of a copy-paste as the asm blob was directly derived from the asm blob for vCPU-run. This has not caused any known problems, likely due to compilers aligning variables to 4-byte or 8-byte boundaries and KVM zeroing out struct vcpu_vmx during allocation. I.e. vCPU-run accesses "junk" data, it just happens to always be zero and so doesn't affect the result. [1] https://gcc.gnu.org/ml/gcc-patches/2000-10/msg01127.html Fixes: 52017608da ("KVM: nVMX: add option to perform early consistency checks via H/W") Cc: <stable@vger.kernel.org> Reviewed-by: Jim Mattson <jmattson@google.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>		2019-02-12 13:12:13 +01:00
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capabilities.h
evmcs.c	x86/kvm/hyper-v: nested_enable_evmcs() sets vmcs_version incorrectly	2019-01-25 19:11:37 +01:00
evmcs.h
nested.c	KVM: nVMX: Check a single byte for VMCS "launched" in nested early checks	2019-02-12 13:12:13 +01:00
nested.h
ops.h
pmu_intel.c
vmcs12.c
vmcs12.h
vmcs_shadow_fields.h
vmcs.h
vmenter.S
vmx.c	KVM: VMX: Compare only a single byte for VMCS' "launched" in vCPU-run	2019-02-12 13:12:12 +01:00
vmx.h