On Wed, Feb 07, 2024, Xin Li wrote:
> @@ -6856,13 +6865,17 @@ static void nested_vmx_setup_exit_ctls(struct
> vmcs_config *vmcs_conf,
> VM_EXIT_HOST_ADDR_SPACE_SIZE |
> #endif
> VM_EXIT_LOAD_IA32_PAT | VM_EXIT_SAVE_IA32_PAT |
> - VM_EXIT_CLEAR_BNDCFGS;
> + VM_EXIT_CLEAR_BNDCFGS | VM_EXIT_ACTIVATE_SECONDARY_CONTROLS;
> msrs->exit_ctls_high |=
> VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR |
> VM_EXIT_LOAD_IA32_EFER | VM_EXIT_SAVE_IA32_EFER |
> VM_EXIT_SAVE_VMX_PREEMPTION_TIMER | VM_EXIT_ACK_INTR_ON_EXIT |
> VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL;
>
> + /* secondary exit controls */
Drop the comment, it's pretty obvious what field is being setup.
> + if (msrs->exit_ctls_high & VM_EXIT_ACTIVATE_SECONDARY_CONTROLS)
> + rdmsrl(MSR_IA32_VMX_EXIT_CTLS2, msrs->secondary_exit_ctls);
This is wrong, the resulting msrs->secondary_exit_ctls needs to be sanitized
based on what KVM supports for nVMX.
On a very related topic, this should not do a raw RDMSR. One of the reasons why
KVM uses vmcs_config as the base is to avoid advertising features to L1 that KVM
itself doesn't support, e.g. because the expected entry+exit pairs aren't
supported.
And by pulling state from vmcs_conf->secondary_exit_ctls there's no need to
check
the activation bit.
I.e. literaly just this:
msrs->secondary_exit_ctls = vmcs_conf->secondary_exit_ctls;
msrs->secondary_exit_ctls &= 0;
and then when nVMX FRED support is ready, it becomes:
msrs->secondary_exit_ctls = vmcs_conf->secondary_exit_ctls;
msrs->secondary_exit_ctls &= SECONDARY_VM_EXIT_SAVE_IA32_FRED |
SECONDARY_VM_EXIT_LOAD_IA32_FRED;
