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Liran Alon authored
If KVM enable_vmware_backdoor module parameter is set, the commit change VMX to now intercept #GP instead of being directly deliviered from CPU to guest. It is done to support access to VMware backdoor I/O ports even if TSS I/O permission denies it. In that case: 1. A #GP will be raised and intercepted. 2. #GP intercept handler will simulate I/O port access instruction. 3. I/O port access instruction simulation will allow access to VMware backdoor ports specifically even if TSS I/O permission bitmap denies it. Note that the above change introduce slight performance hit as now #GPs are not deliviered directly from CPU to guest but instead cause #VMExit and instruction emulation. However, this behavior is introduced only when enable_vmware_backdoor KVM module parameter is set. Signed-off-by:
Liran Alon <liran.alon@oracle.com> Reviewed-by:
Nikita Leshenko <nikita.leshchenko@oracle.com> Reviewed-by:
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by:
Radim Krčmář <rkrcmar@redhat.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
9e869480