diff mbox series

[v6,9/9] KVM: nVMX: Use macros and #defines in vmx_restore_vmx_misc()

Message ID 20240309012725.1409949-10-seanjc@google.com (mailing list archive)
State New, archived
Headers show
Series x86/cpu: KVM: Clean up PAT and VMX macros | expand

Commit Message

Sean Christopherson March 9, 2024, 1:27 a.m. UTC
From: Xin Li <xin3.li@intel.com>

Use macros in vmx_restore_vmx_misc() instead of open coding everything
using BIT_ULL() and GENMASK_ULL().  Opportunistically split feature bits
and reserved bits into separate variables, and add a comment explaining
the subset logic (it's not immediately obvious that the set of feature
bits is NOT the set of _supported_ feature bits).

Cc: Shan Kang <shan.kang@intel.com>
Cc: Kai Huang <kai.huang@intel.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
[sean: split to separate patch, write changelog, drop #defines]
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/vmx/nested.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

Comments

Zhao Liu March 15, 2024, 3:52 p.m. UTC | #1
On Fri, Mar 08, 2024 at 05:27:25PM -0800, Sean Christopherson wrote:
> Date: Fri,  8 Mar 2024 17:27:25 -0800
> From: Sean Christopherson <seanjc@google.com>
> Subject: [PATCH v6 9/9] KVM: nVMX: Use macros and #defines in
>  vmx_restore_vmx_misc()
> X-Mailer: git-send-email 2.44.0.278.ge034bb2e1d-goog
> 
> From: Xin Li <xin3.li@intel.com>
> 
> Use macros in vmx_restore_vmx_misc() instead of open coding everything
> using BIT_ULL() and GENMASK_ULL().  Opportunistically split feature bits
> and reserved bits into separate variables, and add a comment explaining
> the subset logic (it's not immediately obvious that the set of feature
> bits is NOT the set of _supported_ feature bits).
> 
> Cc: Shan Kang <shan.kang@intel.com>
> Cc: Kai Huang <kai.huang@intel.com>
> Signed-off-by: Xin Li <xin3.li@intel.com>
> [sean: split to separate patch, write changelog, drop #defines]
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
>  arch/x86/kvm/vmx/nested.c | 27 ++++++++++++++++++++-------
>  1 file changed, 20 insertions(+), 7 deletions(-)
> 

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Huang, Kai March 27, 2024, 11:02 a.m. UTC | #2
On Fri, 2024-03-08 at 17:27 -0800, Sean Christopherson wrote:
> From: Xin Li <xin3.li@intel.com>
> 
> Use macros in vmx_restore_vmx_misc() instead of open coding everything
> using BIT_ULL() and GENMASK_ULL().  Opportunistically split feature bits
> and reserved bits into separate variables, and add a comment explaining
> the subset logic (it's not immediately obvious that the set of feature
> bits is NOT the set of _supported_ feature bits).
> 
> Cc: Shan Kang <shan.kang@intel.com>
> Cc: Kai Huang <kai.huang@intel.com>
> Signed-off-by: Xin Li <xin3.li@intel.com>
> [sean: split to separate patch, write changelog, drop #defines]
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> 

Reviewed-by: Kai Huang <kai.huang@intel.com>
Xiaoyao Li April 1, 2024, 7:09 a.m. UTC | #3
On 3/9/2024 9:27 AM, Sean Christopherson wrote:
> From: Xin Li <xin3.li@intel.com>
> 
> Use macros in vmx_restore_vmx_misc() instead of open coding everything
> using BIT_ULL() and GENMASK_ULL().  Opportunistically split feature bits
> and reserved bits into separate variables, and add a comment explaining
> the subset logic (it's not immediately obvious that the set of feature
> bits is NOT the set of _supported_ feature bits).
> 
> Cc: Shan Kang <shan.kang@intel.com>
> Cc: Kai Huang <kai.huang@intel.com>
> Signed-off-by: Xin Li <xin3.li@intel.com>
> [sean: split to separate patch, write changelog, drop #defines]
> Signed-off-by: Sean Christopherson <seanjc@google.com>

Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>

> ---
>   arch/x86/kvm/vmx/nested.c | 27 ++++++++++++++++++++-------
>   1 file changed, 20 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 06512ee7a5c4..6610d258c680 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -1322,16 +1322,29 @@ vmx_restore_control_msr(struct vcpu_vmx *vmx, u32 msr_index, u64 data)
>   
>   static int vmx_restore_vmx_misc(struct vcpu_vmx *vmx, u64 data)
>   {
> -	const u64 feature_and_reserved_bits =
> -		/* feature */
> -		BIT_ULL(5) | GENMASK_ULL(8, 6) | BIT_ULL(14) | BIT_ULL(15) |
> -		BIT_ULL(28) | BIT_ULL(29) | BIT_ULL(30) |
> -		/* reserved */
> -		GENMASK_ULL(13, 9) | BIT_ULL(31);
> +	const u64 feature_bits = VMX_MISC_SAVE_EFER_LMA |
> +				 VMX_MISC_ACTIVITY_HLT |
> +				 VMX_MISC_ACTIVITY_SHUTDOWN |
> +				 VMX_MISC_ACTIVITY_WAIT_SIPI |
> +				 VMX_MISC_INTEL_PT |
> +				 VMX_MISC_RDMSR_IN_SMM |
> +				 VMX_MISC_VMWRITE_SHADOW_RO_FIELDS |
> +				 VMX_MISC_VMXOFF_BLOCK_SMI |
> +				 VMX_MISC_ZERO_LEN_INS;
> +
> +	const u64 reserved_bits = BIT_ULL(31) | GENMASK_ULL(13, 9);
> +
>   	u64 vmx_misc = vmx_control_msr(vmcs_config.nested.misc_low,
>   				       vmcs_config.nested.misc_high);
>   
> -	if (!is_bitwise_subset(vmx_misc, data, feature_and_reserved_bits))
> +	BUILD_BUG_ON(feature_bits & reserved_bits);
> +
> +	/*
> +	 * The incoming value must not set feature bits or reserved bits that
> +	 * aren't allowed/supported by KVM.  Fields, i.e. multi-bit values, are
> +	 * explicitly checked below.
> +	 */
> +	if (!is_bitwise_subset(vmx_misc, data, feature_bits | reserved_bits))
>   		return -EINVAL;
>   
>   	if ((vmx->nested.msrs.pinbased_ctls_high &
diff mbox series

Patch

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 06512ee7a5c4..6610d258c680 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -1322,16 +1322,29 @@  vmx_restore_control_msr(struct vcpu_vmx *vmx, u32 msr_index, u64 data)
 
 static int vmx_restore_vmx_misc(struct vcpu_vmx *vmx, u64 data)
 {
-	const u64 feature_and_reserved_bits =
-		/* feature */
-		BIT_ULL(5) | GENMASK_ULL(8, 6) | BIT_ULL(14) | BIT_ULL(15) |
-		BIT_ULL(28) | BIT_ULL(29) | BIT_ULL(30) |
-		/* reserved */
-		GENMASK_ULL(13, 9) | BIT_ULL(31);
+	const u64 feature_bits = VMX_MISC_SAVE_EFER_LMA |
+				 VMX_MISC_ACTIVITY_HLT |
+				 VMX_MISC_ACTIVITY_SHUTDOWN |
+				 VMX_MISC_ACTIVITY_WAIT_SIPI |
+				 VMX_MISC_INTEL_PT |
+				 VMX_MISC_RDMSR_IN_SMM |
+				 VMX_MISC_VMWRITE_SHADOW_RO_FIELDS |
+				 VMX_MISC_VMXOFF_BLOCK_SMI |
+				 VMX_MISC_ZERO_LEN_INS;
+
+	const u64 reserved_bits = BIT_ULL(31) | GENMASK_ULL(13, 9);
+
 	u64 vmx_misc = vmx_control_msr(vmcs_config.nested.misc_low,
 				       vmcs_config.nested.misc_high);
 
-	if (!is_bitwise_subset(vmx_misc, data, feature_and_reserved_bits))
+	BUILD_BUG_ON(feature_bits & reserved_bits);
+
+	/*
+	 * The incoming value must not set feature bits or reserved bits that
+	 * aren't allowed/supported by KVM.  Fields, i.e. multi-bit values, are
+	 * explicitly checked below.
+	 */
+	if (!is_bitwise_subset(vmx_misc, data, feature_bits | reserved_bits))
 		return -EINVAL;
 
 	if ((vmx->nested.msrs.pinbased_ctls_high &