diff mbox series

[7/8] KVM: VMX: Expose TSC scaling to L2

Message ID 20210506103228.67864-8-ilstam@mailbox.org (mailing list archive)
State New, archived
Headers show
Series KVM: VMX: Implement nested TSC scaling | expand

Commit Message

ilstam@mailbox.org May 6, 2021, 10:32 a.m. UTC 
From: Ilias Stamatis <ilstam@amazon.com>

Expose the TSC scaling feature to nested guests.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>
---
 arch/x86/kvm/vmx/nested.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Comments

Maxim Levitsky May 10, 2021, 1:56 p.m. UTC | #1 
On Thu, 2021-05-06 at 10:32 +0000, ilstam@mailbox.org wrote:
> From: Ilias Stamatis <ilstam@amazon.com>
> 
> Expose the TSC scaling feature to nested guests.
> 
> Signed-off-by: Ilias Stamatis <ilstam@amazon.com>
> ---
>  arch/x86/kvm/vmx/nested.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index a1bf28f33837..639cb9462103 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -2277,7 +2277,8 @@ static void prepare_vmcs02_early(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
>  				  SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE |
>  				  SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
>  				  SECONDARY_EXEC_APIC_REGISTER_VIRT |
> -				  SECONDARY_EXEC_ENABLE_VMFUNC);
> +				  SECONDARY_EXEC_ENABLE_VMFUNC |
> +				  SECONDARY_EXEC_TSC_SCALING);
>  		if (nested_cpu_has(vmcs12,
>  				   CPU_BASED_ACTIVATE_SECONDARY_CONTROLS))
>  			exec_control |= vmcs12->secondary_vm_exec_control;
> @@ -6483,7 +6484,8 @@ void nested_vmx_setup_ctls_msrs(struct nested_vmx_msrs *msrs, u32 ept_caps)
>  		SECONDARY_EXEC_RDRAND_EXITING |
>  		SECONDARY_EXEC_ENABLE_INVPCID |
>  		SECONDARY_EXEC_RDSEED_EXITING |
> -		SECONDARY_EXEC_XSAVES;
> +		SECONDARY_EXEC_XSAVES |
> +		SECONDARY_EXEC_TSC_SCALING;
>  
>  	/*
>  	 * We can emulate "VMCS shadowing," even if the hardware


Seems to be correct. I don't yet have experience with how VMX does the VMX capablity
msrs and primary/secondary/entry/exit/pinbased control fitering for features that are not supported on the host,
but after digging through it this seems to be OK.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>

Best regards,
	Maxim Levitsky
diff mbox series

Patch

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index a1bf28f33837..639cb9462103 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2277,7 +2277,8 @@  static void prepare_vmcs02_early(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
 				  SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE |
 				  SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
 				  SECONDARY_EXEC_APIC_REGISTER_VIRT |
-				  SECONDARY_EXEC_ENABLE_VMFUNC);
+				  SECONDARY_EXEC_ENABLE_VMFUNC |
+				  SECONDARY_EXEC_TSC_SCALING);
 		if (nested_cpu_has(vmcs12,
 				   CPU_BASED_ACTIVATE_SECONDARY_CONTROLS))
 			exec_control |= vmcs12->secondary_vm_exec_control;
@@ -6483,7 +6484,8 @@  void nested_vmx_setup_ctls_msrs(struct nested_vmx_msrs *msrs, u32 ept_caps)
 		SECONDARY_EXEC_RDRAND_EXITING |
 		SECONDARY_EXEC_ENABLE_INVPCID |
 		SECONDARY_EXEC_RDSEED_EXITING |
-		SECONDARY_EXEC_XSAVES;
+		SECONDARY_EXEC_XSAVES |
+		SECONDARY_EXEC_TSC_SCALING;
 
 	/*
 	 * We can emulate "VMCS shadowing," even if the hardware