github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-07-28 01:55:51 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

KVM: x86/mmu: separate more EPT/non-EPT permission_fault()

Browse Source 
Move more of EPT handling entirely in the existing "if (!ept)"
conditional.  Use a new "rf" variable instead of uf for read permissions
for clarity.

Merge smepf and ff into a single variable because EPT's "SMEP" (actually
MBEC) is defined differently and does not need smepf.

Tested-by: David Riley <d.riley@proxmox.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2026-05-01 00:02:12 -04:00
parent 296b29597d
commit 949aa12e03
1 changed files with 15 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
arch/x86/kvm/mmu/mmu.c
View File

@ -5584,24 +5584,28 @@ static void update_permission_bitmask(struct kvm_mmu *mmu, bool ept)
* that causes a fault with the given PFEC.
*/
/* Faults from reads to non-readable pages */
u8 rf = 0;
/* Faults from writes to non-writable pages */
u8 wf = (pfec & PFERR_WRITE_MASK) ? (u8)~w : 0;
/* Faults from user mode accesses to supervisor pages */
u8 uf = (pfec & PFERR_USER_MASK) ? (u8)~u : 0;
/* Faults from fetches of non-executable pages*/
u8 ff = (pfec & PFERR_FETCH_MASK) ? (u8)~x : 0;
/* Faults from kernel mode fetches of user pages */
u8 smepf = 0;
u8 uf = 0;
/* Faults from fetches of non-executable pages */
u8 ff = 0;
/* Faults from kernel mode accesses of user pages */
u8 smapf = 0;
if (!ept) {
if (ept) {
rf = (pfec & PFERR_USER_MASK) ? (u8)~u : 0;
ff = (pfec & PFERR_FETCH_MASK) ? (u8)~x : 0;
} else {
/* Faults from kernel mode accesses to user pages */
u8 kf = (pfec & PFERR_USER_MASK) ? 0 : u;
/* Not really needed: !nx will cause pte.nx to fault */
if (!efer_nx)
ff = 0;
uf = (pfec & PFERR_USER_MASK) ? (u8)~u : 0;
if (efer_nx)
ff |= (pfec & PFERR_FETCH_MASK) ? (u8)~x : 0;
/* Allow supervisor writes if !cr0.wp */
if (!cr0_wp)
@ -5609,7 +5613,7 @@ static void update_permission_bitmask(struct kvm_mmu *mmu, bool ept)
/* Disallow supervisor fetches of user code if cr4.smep */
if (cr4_smep)
smepf = (pfec & PFERR_FETCH_MASK) ? kf : 0;
ff |= (pfec & PFERR_FETCH_MASK) ? kf : 0;
/*
* SMAP:kernel-mode data accesses from user-mode
@ -5630,7 +5634,7 @@ static void update_permission_bitmask(struct kvm_mmu *mmu, bool ept)
smapf = (pfec & (PFERR_RSVD_MASK|PFERR_FETCH_MASK)) ? 0 : kf;
}
mmu->permissions[index] = ff | uf | wf | smepf | smapf;
mmu->permissions[index] = ff | uf | wf | rf | smapf;
}
}