| Message ID | 20200320212833.3507-7-sean.j.christopherson@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86: TLB flushing fixes and enhancements | expand |
On 20/03/20 22:28, Sean Christopherson wrote: > +void kvm_inject_l1_page_fault(struct kvm_vcpu *vcpu, > + struct x86_exception *fault) > +{ > + vcpu->arch.mmu->inject_page_fault(vcpu, fault); > +} > + > bool kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu, > struct x86_exception *fault) > { > @@ -619,7 +625,7 @@ bool kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu, > if (mmu_is_nested(vcpu) && !fault->nested_page_fault) > vcpu->arch.nested_mmu.inject_page_fault(vcpu, fault); > else > - vcpu->arch.mmu->inject_page_fault(vcpu, fault); > + kvm_inject_l1_page_fault(vcpu, fault); > > return fault->nested_page_fault; This all started with "I don't like the name of the function" but thinking more about it, we can also write this as if (mmu_is_nested(vcpu) && !fault->nested_page_fault) vcpu->arch.walk_mmu->inject_page_fault(vcpu, fault); else vcpu->arch.mmu->inject_page_fault(vcpu, fault); Now, if !mmu_is_nested(vcpu) then walk_mmu == mmu, so it's much simpler up until this patch: fault_mmu = fault->nested_page_fault ? vcpu->arch.mmu : vcpu->arch.walk_mmu; fault_mmu->inject_page_fault(vcpu, fault); (which also matches how fault->nested_page_fault is assigned to). In patch 7 we add the invalidation in kvm_inject_l1_page_fault, but is it necessary to do it only in the else? + if (!vcpu->arch.mmu->direct_map && + (fault->error_code & PFERR_PRESENT_MASK)) + vcpu->arch.mmu->invlpg(vcpu, fault->address, + vcpu->arch.mmu->root_hpa); + vcpu->arch.mmu->inject_page_fault(vcpu, fault); } The direct_map check is really just an optimization to avoid a retpoline if ->invlpg is nonpaging_invlpg. We can change it to !vcpu->arch.mmu->invlpg if nonpaging_invlpg is replaced with NULL, and then the same "if" condition can also be used for the nested_mmu i.e. what patch 7 writes as + /* + * No need to sync SPTEs, the fault is being injected into L2, + * whose page tables are not being shadowed. + */ vcpu->arch.nested_mmu.inject_page_fault(vcpu, fault); Finally, patch 7 also adds a tlb_flush_gva call which is already present in kvm_mmu_invlpg, and this brings the final form to look like this: bool kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault) { struct kvm_mmu *fault_mmu; WARN_ON_ONCE(fault->vector != PF_VECTOR); fault_mmu = fault->nested_page_fault ? vcpu->arch.mmu : vcpu->arch.walk_mmu; /* * Invalidate the TLB entry for the faulting address, if it exists, * else the access will fault indefinitely (and to emulate hardware). */ if (fault->error_code & PFERR_PRESENT_MASK) __kvm_mmu_invlpg(vcpu, fault_mmu, fault->address); fault_mmu->inject_page_fault(vcpu, fault); return fault->nested_page_fault; } This will become a formal mini-series replacing patches 6 and 7 after I test it, so no need to do anything on your part. Paolo
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 328b1765ff76..cdbf822c5c8b 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1447,6 +1447,8 @@ void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code); void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned nr); void kvm_requeue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code); void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault); +void kvm_inject_l1_page_fault(struct kvm_vcpu *vcpu, + struct x86_exception *fault); bool kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault); int kvm_read_guest_page_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 560e85ebdf22..5ae620881bbc 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4357,12 +4357,6 @@ static unsigned long get_cr3(struct kvm_vcpu *vcpu) return kvm_read_cr3(vcpu); } -static void inject_page_fault(struct kvm_vcpu *vcpu, - struct x86_exception *fault) -{ - vcpu->arch.mmu->inject_page_fault(vcpu, fault); -} - static bool sync_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn, unsigned int access, int *nr_present) { diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index 1ddbfff64ccc..ac613f2fae01 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -812,7 +812,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t addr, u32 error_code, if (!r) { pgprintk("%s: guest page fault\n", __func__); if (!prefault) - inject_page_fault(vcpu, &walker.fault); + kvm_inject_l1_page_fault(vcpu, &walker.fault); return RET_PF_RETRY; } diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 64ed6e6e2b56..fcad522f221e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -611,6 +611,12 @@ void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault) } EXPORT_SYMBOL_GPL(kvm_inject_page_fault); +void kvm_inject_l1_page_fault(struct kvm_vcpu *vcpu, + struct x86_exception *fault) +{ + vcpu->arch.mmu->inject_page_fault(vcpu, fault); +} + bool kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault) { @@ -619,7 +625,7 @@ bool kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu, if (mmu_is_nested(vcpu) && !fault->nested_page_fault) vcpu->arch.nested_mmu.inject_page_fault(vcpu, fault); else - vcpu->arch.mmu->inject_page_fault(vcpu, fault); + kvm_inject_l1_page_fault(vcpu, fault); return fault->nested_page_fault; }
Move the MMU's inject_page_fault(), which is used to inject page faults encountered when walking L1's page tables, to x86.c and use it to handle the non-nested path of kvm_inject_emulated_page_fault(). Using a common helper will reduce duplicate code in a future patch to sync SPTEs on emulated page faults, and also eliminates the rather confusing function name "inject_page_fault", which collides with struct kvm_mmu's hook. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> --- arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/kvm/mmu/mmu.c | 6 ------ arch/x86/kvm/mmu/paging_tmpl.h | 2 +- arch/x86/kvm/x86.c | 8 +++++++- 4 files changed, 10 insertions(+), 8 deletions(-)