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7317f5b143
init_vmcs_control_fields() sets PFEC_MASK and PFEC_MATCH so that they
never match, which reverses the meaning of the PF_VECTOR bit in
EXCEPTION_BITMAP (which is zeroed), effectively enabling #PF
interception by default.
The relevant part of the SDM describes this:
When a page fault occurs, a processor consults (1) bit 14 of the
exception bitmap; (2) the error code produced with the page fault [PFEC];
(3) the page-fault error-code mask field [PFEC_MASK]; and (4) the
page-fault error-code match field [PFEC_MATCH].
It checks if PFEC & PFEC_MASK = PFEC_MATCH. If there is equality, the
specification of bit 14 in the exception bitmap is followed (for example,
a VM exit occurs if that bit is set). If there is inequality, the meaning
of that bit is reversed (for example, a VM exit occurs if that bit is
clear).
Clear PFEC_MATCH such that there is equality, and the #PF bit in the
exception bitmap is followed, so that #PFs are not intercepted by default,
same as every other exception. This also allows tests to set the #PF bit
in the exception bitmap if they want to intercept #PFs, without having to
muck with the PFEC_{MASK,MATCH} fields.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260728174232.2423257-10-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
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| .. | ||
| apic.c | ||
| handlers.S | ||
| hyperv.c | ||
| memstress.c | ||
| pmu.c | ||
| processor.c | ||
| sev.c | ||
| svm.c | ||
| ucall.c | ||
| vmx.c | ||