KVM: MIPS/MMU: Convert TLB mapped faults to page tables

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

1 files changed, 34 insertions, 59 deletions

diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
index afb47f21d8bc..62122d297e52 100644
--- a/arch/mips/kvm/mmu.c
+++ b/arch/mips/kvm/mmu.c
@@ -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());