Commit c97b106f authored by Xin Li's avatar Xin Li Committed by Sean Christopherson
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KVM: nVMX: Use macros and #defines in vmx_restore_vmx_basic() 



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: default avatarXin Li <xin3.li@intel.com>
[sean: split to separate patch, write changelog, drop #defines]
Reviewed-by: default avatarZhao Liu <zhao1.liu@intel.com>
Reviewed-by: default avatarXiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: default avatarKai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20240605231918.2915961-7-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 9df398ff

arch/x86/kvm/vmx/nested.c

+18 −7
Original line number Diff line number Diff line
@@ -1251,21 +1251,32 @@ 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) !=