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KVM: nVMX: Decouple EPT RWX bits from EPT Violation protection bits

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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: Nikolay Borisov <nik.borisov@suse.com>
Link: https://lore.kernel.org/r/20250227000705.3199706-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson
2025-02-26 16:07:05 -08:00
parent fa6c8fc2d2
commit 61146f67e4
3 changed files with 13 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
arch/x86/include/asm/vmx.h
View File

@@ -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
*/

3
arch/x86/kvm/mmu/paging_tmpl.h
View File

@@ -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;

2
arch/x86/kvm/vmx/vmx.c
View File

@@ -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)