From: Xin Li <[email protected]>
Use macros in vmx_restore_vmx_basic() 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 <[email protected]>
Cc: Kai Huang <[email protected]>
Signed-off-by: Xin Li <[email protected]>
[sean: split to separate patch, write changelog, drop #defines]
Signed-off-by: Sean Christopherson <[email protected]>
---
arch/x86/kvm/vmx/nested.c | 25 ++++++++++++++++++-------
1 file changed, 18 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 82a35aba7d2b..4ad8696c25af 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -1228,21 +1228,32 @@ static bool is_bitwise_subset(u64 superset, u64 subset, u64 mask)
static int vmx_restore_vmx_basic(struct vcpu_vmx *vmx, u64 data)
{
- const u64 feature_and_reserved =
- /* feature (except bit 48; see below) */
- BIT_ULL(49) | BIT_ULL(54) | BIT_ULL(55) |
- /* reserved */
- BIT_ULL(31) | GENMASK_ULL(47, 45) | GENMASK_ULL(63, 56);
+ const u64 feature_bits = VMX_BASIC_DUAL_MONITOR_TREATMENT |
+ VMX_BASIC_INOUT |
+ VMX_BASIC_TRUE_CTLS;
+
+ const u64 reserved_bits = GENMASK_ULL(63, 56) |
+ GENMASK_ULL(47, 45) |
+ BIT_ULL(31);
+
u64 vmx_basic = vmcs_config.nested.basic;
- if (!is_bitwise_subset(vmx_basic, data, feature_and_reserved))
+ BUILD_BUG_ON(feature_bits & reserved_bits);
+
+ /*
+ * Except for 32BIT_PHYS_ADDR_ONLY, which is an anti-feature bit (has
+ * inverted polarity), 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_basic, data, feature_bits | reserved_bits))
return -EINVAL;
/*
* KVM does not emulate a version of VMX that constrains physical
* addresses of VMX structures (e.g. VMCS) to 32-bits.
*/
- if (data & BIT_ULL(48))
+ if (data & VMX_BASIC_32BIT_PHYS_ADDR_ONLY)
return -EINVAL;
if (vmx_basic_vmcs_revision_id(vmx_basic) !=
--
2.44.0.278.ge034bb2e1d-goog
On Fri, Mar 08, 2024 at 05:27:22PM -0800, Sean Christopherson wrote:
> Date: Fri, 8 Mar 2024 17:27:22 -0800
> From: Sean Christopherson <[email protected]>
> Subject: [PATCH v6 6/9] KVM: nVMX: Use macros and #defines in
> vmx_restore_vmx_basic()
> X-Mailer: git-send-email 2.44.0.278.ge034bb2e1d-goog
>
> From: Xin Li <[email protected]>
>
> Use macros in vmx_restore_vmx_basic() 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 <[email protected]>
> Cc: Kai Huang <[email protected]>
> Signed-off-by: Xin Li <[email protected]>
> [sean: split to separate patch, write changelog, drop #defines]
> Signed-off-by: Sean Christopherson <[email protected]>
> ---
> arch/x86/kvm/vmx/nested.c | 25 ++++++++++++++++++-------
> 1 file changed, 18 insertions(+), 7 deletions(-)
Reviewed-by: Zhao Liu <[email protected]>
On Fri, 2024-03-08 at 17:27 -0800, Sean Christopherson wrote:
> From: Xin Li <[email protected]>
>
> Use macros in vmx_restore_vmx_basic() 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 <[email protected]>
> Cc: Kai Huang <[email protected]>
> Signed-off-by: Xin Li <[email protected]>
> [sean: split to separate patch, write changelog, drop #defines]
> Signed-off-by: Sean Christopherson <[email protected]>
>
Reviewed-by: Kai Huang <[email protected]>
On 3/9/2024 9:27 AM, Sean Christopherson wrote:
> From: Xin Li <[email protected]>
>
> Use macros in vmx_restore_vmx_basic() 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 <[email protected]>
> Cc: Kai Huang <[email protected]>
> Signed-off-by: Xin Li <[email protected]>
> [sean: split to separate patch, write changelog, drop #defines]
> Signed-off-by: Sean Christopherson <[email protected]>
Reviewed-by: Xiaoyao Li <[email protected]>
> ---
> arch/x86/kvm/vmx/nested.c | 25 ++++++++++++++++++-------
> 1 file changed, 18 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 82a35aba7d2b..4ad8696c25af 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -1228,21 +1228,32 @@ static bool is_bitwise_subset(u64 superset, u64 subset, u64 mask)
>
> static int vmx_restore_vmx_basic(struct vcpu_vmx *vmx, u64 data)
> {
> - const u64 feature_and_reserved =
> - /* feature (except bit 48; see below) */
> - BIT_ULL(49) | BIT_ULL(54) | BIT_ULL(55) |
> - /* reserved */
> - BIT_ULL(31) | GENMASK_ULL(47, 45) | GENMASK_ULL(63, 56);
> + const u64 feature_bits = VMX_BASIC_DUAL_MONITOR_TREATMENT |
> + VMX_BASIC_INOUT |
> + VMX_BASIC_TRUE_CTLS;
> +
> + const u64 reserved_bits = GENMASK_ULL(63, 56) |
> + GENMASK_ULL(47, 45) |
> + BIT_ULL(31);
> +
> u64 vmx_basic = vmcs_config.nested.basic;
>
> - if (!is_bitwise_subset(vmx_basic, data, feature_and_reserved))
> + BUILD_BUG_ON(feature_bits & reserved_bits);
> +
> + /*
> + * Except for 32BIT_PHYS_ADDR_ONLY, which is an anti-feature bit (has
> + * inverted polarity), 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_basic, data, feature_bits | reserved_bits))
> return -EINVAL;
>
> /*
> * KVM does not emulate a version of VMX that constrains physical
> * addresses of VMX structures (e.g. VMCS) to 32-bits.
> */
> - if (data & BIT_ULL(48))
> + if (data & VMX_BASIC_32BIT_PHYS_ADDR_ONLY)
> return -EINVAL;
>
> if (vmx_basic_vmcs_revision_id(vmx_basic) !=