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authorJames Hogan <james.hogan@imgtec.com>2016-12-06 14:59:43 +0000
committerJames Hogan <james.hogan@imgtec.com>2017-02-03 15:21:27 +0000
commitf9b11e51f89f6d2eca2ca8f41bb0ceb07c943e60 (patch)
treec4138efee7e3f28af17d439c8a79c98304b78eaf /arch/mips
parentb584f460e6d6f1bf968acfcd23aceb663ba996fa (diff)
KVM: MIPS/MMU: Pass GPA PTE bits to mapped GVA PTEs
Propagate the GPA PTE protection bits on to the GVA PTEs on a mapped fault (except _PAGE_WRITE, and filtered by the guest TLB entry), rather than always overriding the protection. This allows dirty page tracking to work in mapped guest segments as a clear dirty bit in the GPA PTE will propagate to the GVA PTEs even when the guest TLB has the dirty bit set. Since the filtering of protection bits is now abstracted, if the buddy GVA PTE is also valid, we obtain the corresponding GPA PTE using a simple non-allocating walk and load that into the GVA PTE similarly (which may itself be invalid). 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
Diffstat (limited to 'arch/mips')
-rw-r--r--arch/mips/kvm/mmu.c56
1 files changed, 37 insertions, 19 deletions
diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
index 9cc941864aa8..8a01bbd276fc 100644
--- a/arch/mips/kvm/mmu.c
+++ b/arch/mips/kvm/mmu.c
@@ -782,6 +782,15 @@ static pte_t kvm_mips_gpa_pte_to_gva_unmapped(pte_t pte)
return pte;
}
+static pte_t kvm_mips_gpa_pte_to_gva_mapped(pte_t pte, long entrylo)
+{
+ /* Guest EntryLo overrides host EntryLo */
+ if (!(entrylo & ENTRYLO_D))
+ pte = pte_mkclean(pte);
+
+ return kvm_mips_gpa_pte_to_gva_unmapped(pte);
+}
+
/* XXXKYMA: Must be called with interrupts disabled */
int kvm_mips_handle_kseg0_tlb_fault(unsigned long badvaddr,
struct kvm_vcpu *vcpu,
@@ -825,39 +834,48 @@ int kvm_mips_handle_mapped_seg_tlb_fault(struct kvm_vcpu *vcpu,
unsigned long gva,
bool write_fault)
{
- kvm_pfn_t pfn;
- long tlb_lo = 0;
- pte_t pte_gpa, *ptep_gva;
- unsigned int idx;
+ struct kvm *kvm = vcpu->kvm;
+ long tlb_lo[2];
+ pte_t pte_gpa[2], *ptep_buddy, *ptep_gva;
+ unsigned int idx = TLB_LO_IDX(*tlb, gva);
bool kernel = KVM_GUEST_KERNEL_MODE(vcpu);
+ tlb_lo[0] = tlb->tlb_lo[0];
+ tlb_lo[1] = tlb->tlb_lo[1];
+
/*
* The commpage address must not be mapped to anything else if the guest
* TLB contains entries nearby, or commpage accesses will break.
*/
- idx = TLB_LO_IDX(*tlb, gva);
- if ((gva ^ KVM_GUEST_COMMPAGE_ADDR) & VPN2_MASK & PAGE_MASK)
- tlb_lo = tlb->tlb_lo[idx];
+ if (!((gva ^ KVM_GUEST_COMMPAGE_ADDR) & VPN2_MASK & (PAGE_MASK << 1)))
+ tlb_lo[TLB_LO_IDX(*tlb, KVM_GUEST_COMMPAGE_ADDR)] = 0;
- /* Find host PFN */
- if (kvm_mips_map_page(vcpu, mips3_tlbpfn_to_paddr(tlb_lo), write_fault,
- &pte_gpa, NULL) < 0)
+ /* Get the GPA page table entry */
+ if (kvm_mips_map_page(vcpu, mips3_tlbpfn_to_paddr(tlb_lo[idx]),
+ write_fault, &pte_gpa[idx], NULL) < 0)
return -1;
- pfn = pte_pfn(pte_gpa);
- /* Find GVA page table entry */
- ptep_gva = kvm_trap_emul_pte_for_gva(vcpu, gva);
+ /* And its GVA buddy's GPA page table entry if it also exists */
+ pte_gpa[!idx] = pfn_pte(0, __pgprot(0));
+ if (tlb_lo[!idx] & ENTRYLO_V) {
+ spin_lock(&kvm->mmu_lock);
+ ptep_buddy = kvm_mips_pte_for_gpa(kvm, NULL,
+ mips3_tlbpfn_to_paddr(tlb_lo[!idx]));
+ if (ptep_buddy)
+ pte_gpa[!idx] = *ptep_buddy;
+ spin_unlock(&kvm->mmu_lock);
+ }
+
+ /* Get the GVA page table entry pair */
+ ptep_gva = kvm_trap_emul_pte_for_gva(vcpu, gva & ~PAGE_SIZE);
if (!ptep_gva) {
kvm_err("No ptep for gva %lx\n", gva);
return -1;
}
- /* 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));
+ /* Copy a pair of entries from GPA page table to GVA page table */
+ ptep_gva[0] = kvm_mips_gpa_pte_to_gva_mapped(pte_gpa[0], tlb_lo[0]);
+ ptep_gva[1] = kvm_mips_gpa_pte_to_gva_mapped(pte_gpa[1], tlb_lo[1]);
/* Invalidate this entry in the TLB, current guest mode ASID only */
kvm_mips_host_tlb_inv(vcpu, gva, !kernel, kernel);