Commit 61146f67 authored by Sean Christopherson's avatar Sean Christopherson
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KVM: nVMX: Decouple EPT RWX bits from EPT Violation protection bits 



Define independent macros for the RWX protection bits that are enumerated
via EXIT_QUALIFICATION for EPT Violations, and tie them to the RWX bits in
EPT entries via compile-time asserts.  Piggybacking the EPTE defines works
for now, but it creates holes in the EPT_VIOLATION_xxx macros and will
cause headaches if/when KVM emulates Mode-Based Execution (MBEC), or any
other features that introduces additional protection information.

Opportunistically rename EPT_VIOLATION_RWX_MASK to EPT_VIOLATION_PROT_MASK
so that it doesn't become stale if/when MBEC support is added.

No functional change intended.

Cc: Jon Kohler <jon@nutanix.com>
Cc: Nikolay Borisov <nik.borisov@suse.com>
Reviewed-by: default avatarNikolay Borisov <nik.borisov@suse.com>
Link: https://lore.kernel.org/r/20250227000705.3199706-3-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent fa6c8fc2

arch/x86/include/asm/vmx.h

+11 −2
Original line number Diff line number Diff line
@@ -580,14 +580,23 @@ enum vm_entry_failure_code { 
/*

 * Exit Qualifications for EPT Violations

 */

#define EPT_VIOLATION_RWX_SHIFT		3

#define EPT_VIOLATION_ACC_READ		BIT(0)

#define EPT_VIOLATION_ACC_WRITE		BIT(1)

#define EPT_VIOLATION_ACC_INSTR		BIT(2)

#define EPT_VIOLATION_RWX_MASK		(VMX_EPT_RWX_MASK << EPT_VIOLATION_RWX_SHIFT)

#define EPT_VIOLATION_PROT_READ		BIT(3)

#define EPT_VIOLATION_PROT_WRITE	BIT(4)

#define EPT_VIOLATION_PROT_EXEC		BIT(5)

#define EPT_VIOLATION_PROT_MASK		(EPT_VIOLATION_PROT_READ  | \

					 EPT_VIOLATION_PROT_WRITE | \

					 EPT_VIOLATION_PROT_EXEC)

#define EPT_VIOLATION_GVA_IS_VALID	BIT(7)

#define EPT_VIOLATION_GVA_TRANSLATED	BIT(8)



#define EPT_VIOLATION_RWX_TO_PROT(__epte) (((__epte) & VMX_EPT_RWX_MASK) << 3)



static_assert(EPT_VIOLATION_RWX_TO_PROT(VMX_EPT_RWX_MASK) ==

	      (EPT_VIOLATION_PROT_READ | EPT_VIOLATION_PROT_WRITE | EPT_VIOLATION_PROT_EXEC));



/*

 * Exit Qualifications for NOTIFY VM EXIT

 */

arch/x86/kvm/mmu/paging_tmpl.h

+1 −2
Original line number Diff line number Diff line
@@ -510,8 +510,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, 
		 * Note, pte_access holds the raw RWX bits from the EPTE, not

		 * ACC_*_MASK flags!

		 */

		walker->fault.exit_qualification |= (pte_access & VMX_EPT_RWX_MASK) <<

						     EPT_VIOLATION_RWX_SHIFT;

		walker->fault.exit_qualification |= EPT_VIOLATION_RWX_TO_PROT(pte_access);

	}

#endif

	walker->fault.address = addr;

arch/x86/kvm/vmx/vmx.c

+1 −1
Original line number Diff line number Diff line
@@ -5822,7 +5822,7 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu) 
	error_code |= (exit_qualification & EPT_VIOLATION_ACC_INSTR)

		      ? PFERR_FETCH_MASK : 0;

	/* ept page table entry is present? */

	error_code |= (exit_qualification & EPT_VIOLATION_RWX_MASK)

	error_code |= (exit_qualification & EPT_VIOLATION_PROT_MASK)

		      ? PFERR_PRESENT_MASK : 0;



	if (error_code & EPT_VIOLATION_GVA_IS_VALID)