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KVM: MIPS/MMU: Convert TLB mapped faults to page tables
authorJames Hogan <james.hogan@imgtec.com>
Sat, 8 Oct 2016 00:15:19 +0000 (01:15 +0100)
committerJames Hogan <james.hogan@imgtec.com>
Fri, 3 Feb 2017 15:20:58 +0000 (15:20 +0000)
Now that we have GVA page tables and an optimised TLB refill handler in
place, convert the handling of page faults in TLB mapped segment from
the guest to fill a single GVA page table entry and invalidate the TLB
entry, rather than filling a TLB entry pair directly.

Also remove the now unused kvm_mips_get_{kernel,user}_asid() functions
in mmu.c and kvm_mips_host_tlb_write() in tlb.c.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
arch/mips/include/asm/kvm_host.h
arch/mips/kvm/emulate.c
arch/mips/kvm/mmu.c
arch/mips/kvm/tlb.c

index 40aab4f..f768099 100644 (file)
@@ -599,7 +599,8 @@ extern int kvm_mips_handle_commpage_tlb_fault(unsigned long badvaddr,
                                              struct kvm_vcpu *vcpu);
 
 extern int kvm_mips_handle_mapped_seg_tlb_fault(struct kvm_vcpu *vcpu,
-                                               struct kvm_mips_tlb *tlb);
+                                               struct kvm_mips_tlb *tlb,
+                                               unsigned long gva);
 
 extern enum emulation_result kvm_mips_handle_tlbmiss(u32 cause,
                                                     u32 *opc,
@@ -613,10 +614,6 @@ extern enum emulation_result kvm_mips_handle_tlbmod(u32 cause,
 
 extern void kvm_mips_dump_host_tlbs(void);
 extern void kvm_mips_dump_guest_tlbs(struct kvm_vcpu *vcpu);
-extern int kvm_mips_host_tlb_write(struct kvm_vcpu *vcpu, unsigned long entryhi,
-                                  unsigned long entrylo0,
-                                  unsigned long entrylo1,
-                                  int flush_dcache_mask);
 extern void kvm_mips_flush_host_tlb(int skip_kseg0);
 extern int kvm_mips_host_tlb_inv(struct kvm_vcpu *vcpu, unsigned long entryhi,
                                 bool user, bool kernel);
index 19eaeda..3ced662 100644 (file)
@@ -1770,7 +1770,8 @@ enum emulation_result kvm_mips_emulate_cache(union mips_instruction inst,
                         * We fault an entry from the guest tlb to the
                         * shadow host TLB
                         */
-                       if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb)) {
+                       if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb,
+                                                                va)) {
                                kvm_err("%s: handling mapped seg tlb fault for %lx, index: %u, vcpu: %p, ASID: %#lx\n",
                                        __func__, va, index, vcpu,
                                        read_c0_entryhi());
@@ -2746,7 +2747,8 @@ enum emulation_result kvm_mips_handle_tlbmiss(u32 cause,
                         * OK we have a Guest TLB entry, now inject it into the
                         * shadow host TLB
                         */
-                       if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb)) {
+                       if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb,
+                                                                va)) {
                                kvm_err("%s: handling mapped seg tlb fault for %lx, index: %u, vcpu: %p, ASID: %#lx\n",
                                        __func__, va, index, vcpu,
                                        read_c0_entryhi());
index afb47f2..62122d2 100644 (file)
@@ -61,22 +61,6 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu)
        mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
 }
 
-static u32 kvm_mips_get_kernel_asid(struct kvm_vcpu *vcpu)
-{
-       struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;
-       int cpu = smp_processor_id();
-
-       return cpu_asid(cpu, kern_mm);
-}
-
-static u32 kvm_mips_get_user_asid(struct kvm_vcpu *vcpu)
-{
-       struct mm_struct *user_mm = &vcpu->arch.guest_user_mm;
-       int cpu = smp_processor_id();
-
-       return cpu_asid(cpu, user_mm);
-}
-
 /**
  * kvm_mips_walk_pgd() - Walk page table with optional allocation.
  * @pgd:       Page directory pointer.
@@ -411,67 +395,58 @@ int kvm_mips_handle_kseg0_tlb_fault(unsigned long badvaddr,
 }
 
 int kvm_mips_handle_mapped_seg_tlb_fault(struct kvm_vcpu *vcpu,
-                                        struct kvm_mips_tlb *tlb)
+                                        struct kvm_mips_tlb *tlb,
+                                        unsigned long gva)
 {
-       unsigned long entryhi = 0, entrylo0 = 0, entrylo1 = 0;
        struct kvm *kvm = vcpu->kvm;
-       kvm_pfn_t pfn0, pfn1;
-       gfn_t gfn0, gfn1;
-       long tlb_lo[2];
-       int ret;
-
-       tlb_lo[0] = tlb->tlb_lo[0];
-       tlb_lo[1] = tlb->tlb_lo[1];
+       kvm_pfn_t pfn;
+       gfn_t gfn;
+       long tlb_lo = 0;
+       pte_t *ptep_gva;
+       unsigned int idx;
+       bool kernel = KVM_GUEST_KERNEL_MODE(vcpu);
 
        /*
         * The commpage address must not be mapped to anything else if the guest
         * TLB contains entries nearby, or commpage accesses will break.
         */
-       if (!((tlb->tlb_hi ^ KVM_GUEST_COMMPAGE_ADDR) &
-                       VPN2_MASK & (PAGE_MASK << 1)))
-               tlb_lo[(KVM_GUEST_COMMPAGE_ADDR >> PAGE_SHIFT) & 1] = 0;
-
-       gfn0 = mips3_tlbpfn_to_paddr(tlb_lo[0]) >> PAGE_SHIFT;
-       gfn1 = mips3_tlbpfn_to_paddr(tlb_lo[1]) >> PAGE_SHIFT;
-       if (gfn0 >= kvm->arch.guest_pmap_npages ||
-           gfn1 >= kvm->arch.guest_pmap_npages) {
-               kvm_err("%s: Invalid gfn: [%#llx, %#llx], EHi: %#lx\n",
-                       __func__, gfn0, gfn1, tlb->tlb_hi);
+       idx = TLB_LO_IDX(*tlb, gva);
+       if ((gva ^ KVM_GUEST_COMMPAGE_ADDR) & VPN2_MASK & PAGE_MASK)
+               tlb_lo = tlb->tlb_lo[idx];
+
+       /* Find host PFN */
+       gfn = mips3_tlbpfn_to_paddr(tlb_lo) >> PAGE_SHIFT;
+       if (gfn >= kvm->arch.guest_pmap_npages) {
+               kvm_err("%s: Invalid gfn: %#llx, EHi: %#lx\n",
+                       __func__, gfn, tlb->tlb_hi);
                kvm_mips_dump_guest_tlbs(vcpu);
                return -1;
        }
-
-       if (kvm_mips_map_page(kvm, gfn0) < 0)
+       if (kvm_mips_map_page(kvm, gfn) < 0)
                return -1;
+       pfn = kvm->arch.guest_pmap[gfn];
 
-       if (kvm_mips_map_page(kvm, gfn1) < 0)
+       /* Find GVA page table entry */
+       ptep_gva = kvm_trap_emul_pte_for_gva(vcpu, gva);
+       if (!ptep_gva) {
+               kvm_err("No ptep for gva %lx\n", gva);
                return -1;
+       }
 
-       pfn0 = kvm->arch.guest_pmap[gfn0];
-       pfn1 = kvm->arch.guest_pmap[gfn1];
+       /* Write PFN into GVA page table, taking attributes from Guest TLB */
+       *ptep_gva = pfn_pte(pfn, (!(tlb_lo & ENTRYLO_V)) ? __pgprot(0) :
+                                (tlb_lo & ENTRYLO_D) ? PAGE_SHARED :
+                                PAGE_READONLY);
+       if (pte_present(*ptep_gva))
+               *ptep_gva = pte_mkyoung(pte_mkdirty(*ptep_gva));
 
-       /* Get attributes from the Guest TLB */
-       entrylo0 = mips3_paddr_to_tlbpfn(pfn0 << PAGE_SHIFT) |
-               ((_page_cachable_default >> _CACHE_SHIFT) << ENTRYLO_C_SHIFT) |
-               (tlb_lo[0] & ENTRYLO_D) |
-               (tlb_lo[0] & ENTRYLO_V);
-       entrylo1 = mips3_paddr_to_tlbpfn(pfn1 << PAGE_SHIFT) |
-               ((_page_cachable_default >> _CACHE_SHIFT) << ENTRYLO_C_SHIFT) |
-               (tlb_lo[1] & ENTRYLO_D) |
-               (tlb_lo[1] & ENTRYLO_V);
+       /* Invalidate this entry in the TLB, current guest mode ASID only */
+       kvm_mips_host_tlb_inv(vcpu, gva, !kernel, kernel);
 
        kvm_debug("@ %#lx tlb_lo0: 0x%08lx tlb_lo1: 0x%08lx\n", vcpu->arch.pc,
                  tlb->tlb_lo[0], tlb->tlb_lo[1]);
 
-       preempt_disable();
-       entryhi = (tlb->tlb_hi & VPN2_MASK) | (KVM_GUEST_KERNEL_MODE(vcpu) ?
-                                              kvm_mips_get_kernel_asid(vcpu) :
-                                              kvm_mips_get_user_asid(vcpu));
-       ret = kvm_mips_host_tlb_write(vcpu, entryhi, entrylo0, entrylo1,
-                                     tlb->tlb_mask);
-       preempt_enable();
-
-       return ret;
+       return 0;
 }
 
 void kvm_get_new_mmu_context(struct mm_struct *mm, unsigned long cpu,
@@ -582,7 +557,7 @@ u32 kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu)
                                return KVM_INVALID_INST;
                        }
                        if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu,
-                                               &vcpu->arch.guest_tlb[index])) {
+                                       &vcpu->arch.guest_tlb[index], va)) {
                                kvm_err("%s: handling mapped seg tlb fault failed for %p, index: %u, vcpu: %p, ASID: %#lx\n",
                                        __func__, opc, index, vcpu,
                                        read_c0_entryhi());
index 06ee9a1..2fb7686 100644 (file)
@@ -104,70 +104,6 @@ void kvm_mips_dump_guest_tlbs(struct kvm_vcpu *vcpu)
 }
 EXPORT_SYMBOL_GPL(kvm_mips_dump_guest_tlbs);
 
-/* XXXKYMA: Must be called with interrupts disabled */
-/* set flush_dcache_mask == 0 if no dcache flush required */
-int kvm_mips_host_tlb_write(struct kvm_vcpu *vcpu, unsigned long entryhi,
-                           unsigned long entrylo0, unsigned long entrylo1,
-                           int flush_dcache_mask)
-{
-       unsigned long flags;
-       unsigned long old_entryhi;
-       int idx;
-
-       local_irq_save(flags);
-
-       old_entryhi = read_c0_entryhi();
-       write_c0_entryhi(entryhi);
-       mtc0_tlbw_hazard();
-
-       tlb_probe();
-       tlb_probe_hazard();
-       idx = read_c0_index();
-
-       if (idx > current_cpu_data.tlbsize) {
-               kvm_err("%s: Invalid Index: %d\n", __func__, idx);
-               kvm_mips_dump_host_tlbs();
-               local_irq_restore(flags);
-               return -1;
-       }
-
-       write_c0_entrylo0(entrylo0);
-       write_c0_entrylo1(entrylo1);
-       mtc0_tlbw_hazard();
-
-       if (idx < 0)
-               tlb_write_random();
-       else
-               tlb_write_indexed();
-       tlbw_use_hazard();
-
-       kvm_debug("@ %#lx idx: %2d [entryhi(R): %#lx] entrylo0(R): 0x%08lx, entrylo1(R): 0x%08lx\n",
-                 vcpu->arch.pc, idx, read_c0_entryhi(),
-                 read_c0_entrylo0(), read_c0_entrylo1());
-
-       /* Flush D-cache */
-       if (flush_dcache_mask) {
-               if (entrylo0 & ENTRYLO_V) {
-                       ++vcpu->stat.flush_dcache_exits;
-                       flush_data_cache_page((entryhi & VPN2_MASK) &
-                                             ~flush_dcache_mask);
-               }
-               if (entrylo1 & ENTRYLO_V) {
-                       ++vcpu->stat.flush_dcache_exits;
-                       flush_data_cache_page(((entryhi & VPN2_MASK) &
-                                              ~flush_dcache_mask) |
-                                             (0x1 << PAGE_SHIFT));
-               }
-       }
-
-       /* Restore old ASID */
-       write_c0_entryhi(old_entryhi);
-       mtc0_tlbw_hazard();
-       local_irq_restore(flags);
-       return 0;
-}
-EXPORT_SYMBOL_GPL(kvm_mips_host_tlb_write);
-
 int kvm_mips_handle_commpage_tlb_fault(unsigned long badvaddr,
        struct kvm_vcpu *vcpu)
 {