iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

KVM: MIPS/MMU: Pass GPA PTE bits to KSeg0 GVA PTEs

Browse Source 
Propagate the GPA PTE protection bits on to the GVA PTEs on a KSeg0
fault (except _PAGE_WRITE), rather than always overriding the
protection. This allows dirty page tracking to work in KSeg0 as a clear
dirty bit in the GPA PTE will propagate to the GVA PTEs.

This makes it simpler to use a single kvm_mips_map_page() to obtain both
the main GPA PTE and its buddy (which may be invalid), which also allows
memory regions to be fully accessible when they don't start and end on a
2*PAGE_SIZE boundary.

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
This commit is contained in:
James Hogan 2016-12-06 14:59:28 +00:00
parent b5f1dd1ba4
commit b584f460e6
1 changed files with 26 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

49
arch/mips/kvm/mmu.c
View File

@ -769,15 +769,27 @@ void kvm_mips_flush_gva_pt(pgd_t *pgd, enum kvm_mips_flush flags)
} }
} }
static pte_t kvm_mips_gpa_pte_to_gva_unmapped(pte_t pte)
{
/*
* Don't leak writeable but clean entries from GPA page tables. We don't
* want the normal Linux tlbmod handler to handle dirtying when KVM
* accesses guest memory.
*/
if (!pte_dirty(pte))
pte = pte_wrprotect(pte);
return pte;
}
/* XXXKYMA: Must be called with interrupts disabled */ /* XXXKYMA: Must be called with interrupts disabled */
int kvm_mips_handle_kseg0_tlb_fault(unsigned long badvaddr, int kvm_mips_handle_kseg0_tlb_fault(unsigned long badvaddr,
struct kvm_vcpu *vcpu, struct kvm_vcpu *vcpu,
bool write_fault) bool write_fault)
{ {
unsigned long gpa; unsigned long gpa;
kvm_pfn_t pfn0, pfn1;
unsigned long vaddr;
pte_t pte_gpa[2], *ptep_gva; pte_t pte_gpa[2], *ptep_gva;
int idx;
if (KVM_GUEST_KSEGX(badvaddr) != KVM_GUEST_KSEG0) { if (KVM_GUEST_KSEGX(badvaddr) != KVM_GUEST_KSEG0) {
kvm_err("%s: Invalid BadVaddr: %#lx\n", __func__, badvaddr); kvm_err("%s: Invalid BadVaddr: %#lx\n", __func__, badvaddr);
@ -785,35 +797,26 @@ int kvm_mips_handle_kseg0_tlb_fault(unsigned long badvaddr,
return -1; return -1;
} }
/* Find host PFNs */ /* Get the GPA page table entry */
gpa = KVM_GUEST_CPHYSADDR(badvaddr);
gpa = KVM_GUEST_CPHYSADDR(badvaddr & (PAGE_MASK << 1)); idx = (badvaddr >> PAGE_SHIFT) & 1;
vaddr = badvaddr & (PAGE_MASK << 1); if (kvm_mips_map_page(vcpu, gpa, write_fault, &pte_gpa[idx],
&pte_gpa[!idx]) < 0)
if (kvm_mips_map_page(vcpu, gpa, write_fault, &pte_gpa[0], NULL) < 0)
return -1; return -1;
if (kvm_mips_map_page(vcpu, gpa | PAGE_SIZE, write_fault, &pte_gpa[1], /* Get the GVA page table entry */
NULL) < 0) ptep_gva = kvm_trap_emul_pte_for_gva(vcpu, badvaddr & ~PAGE_SIZE);
return -1;
pfn0 = pte_pfn(pte_gpa[0]);
pfn1 = pte_pfn(pte_gpa[1]);
/* Find GVA page table entry */
ptep_gva = kvm_trap_emul_pte_for_gva(vcpu, vaddr);
if (!ptep_gva) { if (!ptep_gva) {
kvm_err("No ptep for gva %lx\n", vaddr); kvm_err("No ptep for gva %lx\n", badvaddr);
return -1; return -1;
} }
/* Write host PFNs into GVA page table */ /* Copy a pair of entries from GPA page table to GVA page table */
ptep_gva[0] = pte_mkyoung(pte_mkdirty(pfn_pte(pfn0, PAGE_SHARED))); ptep_gva[0] = kvm_mips_gpa_pte_to_gva_unmapped(pte_gpa[0]);
ptep_gva[1] = pte_mkyoung(pte_mkdirty(pfn_pte(pfn1, PAGE_SHARED))); ptep_gva[1] = kvm_mips_gpa_pte_to_gva_unmapped(pte_gpa[1]);
/* Invalidate this entry in the TLB, guest kernel ASID only */ /* Invalidate this entry in the TLB, guest kernel ASID only */
kvm_mips_host_tlb_inv(vcpu, vaddr, false, true); kvm_mips_host_tlb_inv(vcpu, badvaddr, false, true);
return 0; return 0;
} }