Messages in this thread | | | Date | Mon, 1 Apr 2024 15:00:34 +0800 | Subject | Re: [PATCH v6 6/9] KVM: nVMX: Use macros and #defines in vmx_restore_vmx_basic() | From | Xiaoyao Li <> |
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On 3/9/2024 9:27 AM, Sean Christopherson wrote: > From: Xin Li <xin3.li@intel.com> > > 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 <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 | 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) !=
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