Skip to content

Commit

Permalink
KVM: VMX: introduce vmx_need_pf_intercept
Browse files Browse the repository at this point in the history
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200710154811.418214-7-mgamal@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
  • Loading branch information
Paolo Bonzini committed Jul 10, 2020
1 parent 32de2b5 commit a0c1343
Showing 3 changed files with 23 additions and 12 deletions.
28 changes: 17 additions & 11 deletions arch/x86/kvm/vmx/nested.c
Original file line number Diff line number Diff line change
@@ -2438,22 +2438,28 @@ static void prepare_vmcs02_rare(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)

/*
* Whether page-faults are trapped is determined by a combination of
* 3 settings: PFEC_MASK, PFEC_MATCH and EXCEPTION_BITMAP.PF.
* If enable_ept, L0 doesn't care about page faults and we should
* set all of these to L1's desires. However, if !enable_ept, L0 does
* care about (at least some) page faults, and because it is not easy
* (if at all possible?) to merge L0 and L1's desires, we simply ask
* to exit on each and every L2 page fault. This is done by setting
* MASK=MATCH=0 and (see below) EB.PF=1.
* 3 settings: PFEC_MASK, PFEC_MATCH and EXCEPTION_BITMAP.PF. If L0
* doesn't care about page faults then we should set all of these to
* L1's desires. However, if L0 does care about (some) page faults, it
* is not easy (if at all possible?) to merge L0 and L1's desires, we
* simply ask to exit on each and every L2 page fault. This is done by
* setting MASK=MATCH=0 and (see below) EB.PF=1.
* Note that below we don't need special code to set EB.PF beyond the
* "or"ing of the EB of vmcs01 and vmcs12, because when enable_ept,
* vmcs01's EB.PF is 0 so the "or" will take vmcs12's value, and when
* !enable_ept, EB.PF is 1, so the "or" will always be 1.
*/
vmcs_write32(PAGE_FAULT_ERROR_CODE_MASK,
enable_ept ? vmcs12->page_fault_error_code_mask : 0);
vmcs_write32(PAGE_FAULT_ERROR_CODE_MATCH,
enable_ept ? vmcs12->page_fault_error_code_match : 0);
if (vmx_need_pf_intercept(&vmx->vcpu)) {
/*
* TODO: if both L0 and L1 need the same MASK and MATCH,
* go ahead and use it?
*/
vmcs_write32(PAGE_FAULT_ERROR_CODE_MASK, 0);
vmcs_write32(PAGE_FAULT_ERROR_CODE_MATCH, 0);
} else {
vmcs_write32(PAGE_FAULT_ERROR_CODE_MASK, vmcs12->page_fault_error_code_mask);
vmcs_write32(PAGE_FAULT_ERROR_CODE_MATCH, vmcs12->page_fault_error_code_match);
}

if (cpu_has_vmx_apicv()) {
vmcs_write64(EOI_EXIT_BITMAP0, vmcs12->eoi_exit_bitmap0);
2 changes: 1 addition & 1 deletion arch/x86/kvm/vmx/vmx.c
Original file line number Diff line number Diff line change
@@ -780,7 +780,7 @@ void update_exception_bitmap(struct kvm_vcpu *vcpu)
eb |= 1u << BP_VECTOR;
if (to_vmx(vcpu)->rmode.vm86_active)
eb = ~0;
if (enable_ept)
if (!vmx_need_pf_intercept(vcpu))
eb &= ~(1u << PF_VECTOR);

/* When we are running a nested L2 guest and L1 specified for it a
5 changes: 5 additions & 0 deletions arch/x86/kvm/vmx/vmx.h
Original file line number Diff line number Diff line change
@@ -550,6 +550,11 @@ static inline bool vmx_has_waitpkg(struct vcpu_vmx *vmx)
SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE;
}

static inline bool vmx_need_pf_intercept(struct kvm_vcpu *vcpu)
{
return !enable_ept;
}

void dump_vmcs(void);

#endif /* __KVM_X86_VMX_H */

0 comments on commit a0c1343

Please sign in to comment.