[PATCH v2 15/33] KVM: PPC: Book3S HV: Make kvmppc_mmu_radix_xlate process/partition table agnostic
Paul Mackerras
paulus at ozlabs.org
Fri Sep 28 19:45:45 AEST 2018
From: Suraj Jitindar Singh <sjitindarsingh at gmail.com>
kvmppc_mmu_radix_xlate() is used to translate an effective address
through the process tables. The process table and partition tables have
identical layout. Exploit this fact to make the kvmppc_mmu_radix_xlate()
function able to translate either an effective address through the
process tables or a guest real address through the partition tables.
[paulus at ozlabs.org - reduced diffs from previous code]
Reviewed-by: David Gibson <david at gibson.dropbear.id.au>
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh at gmail.com>
Signed-off-by: Paul Mackerras <paulus at ozlabs.org>
---
arch/powerpc/include/asm/kvm_book3s.h | 3 +
arch/powerpc/kvm/book3s_64_mmu_radix.c | 109 +++++++++++++++++++++++----------
2 files changed, 78 insertions(+), 34 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index dd18d81..91c9779 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -188,6 +188,9 @@ extern int kvmppc_book3s_hcall_implemented(struct kvm *kvm, unsigned long hc);
extern int kvmppc_book3s_radix_page_fault(struct kvm_run *run,
struct kvm_vcpu *vcpu,
unsigned long ea, unsigned long dsisr);
+extern int kvmppc_mmu_radix_translate_table(struct kvm_vcpu *vcpu, gva_t eaddr,
+ struct kvmppc_pte *gpte, u64 table,
+ int table_index, u64 *pte_ret_p);
extern int kvmppc_mmu_radix_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
struct kvmppc_pte *gpte, bool data, bool iswrite);
extern int kvmppc_init_vm_radix(struct kvm *kvm);
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index 71951b5..f2976f4 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -29,83 +29,92 @@
*/
static int p9_supported_radix_bits[4] = { 5, 9, 9, 13 };
-int kvmppc_mmu_radix_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
- struct kvmppc_pte *gpte, bool data, bool iswrite)
+/*
+ * Used to walk a partition or process table radix tree in guest memory
+ * Note: We exploit the fact that a partition table and a process
+ * table have the same layout, a partition-scoped page table and a
+ * process-scoped page table have the same layout, and the 2nd
+ * doubleword of a partition table entry has the same layout as
+ * the PTCR register.
+ */
+int kvmppc_mmu_radix_translate_table(struct kvm_vcpu *vcpu, gva_t eaddr,
+ struct kvmppc_pte *gpte, u64 table,
+ int table_index, u64 *pte_ret_p)
{
struct kvm *kvm = vcpu->kvm;
- u32 pid;
int ret, level, ps;
- __be64 prte, rpte;
- unsigned long ptbl;
- unsigned long root, pte, index;
+ unsigned long ptbl, root;
unsigned long rts, bits, offset;
- unsigned long gpa;
- unsigned long proc_tbl_size;
+ unsigned long size, index;
+ struct prtb_entry entry;
+ u64 pte, base, gpa;
+ __be64 rpte;
- /* Work out effective PID */
- switch (eaddr >> 62) {
- case 0:
- pid = vcpu->arch.pid;
- break;
- case 3:
- pid = 0;
- break;
- default:
+ if ((table & PRTS_MASK) > 24)
return -EINVAL;
- }
- proc_tbl_size = 1 << ((kvm->arch.process_table & PRTS_MASK) + 12);
- if (pid * 16 >= proc_tbl_size)
+ size = 1ul << ((table & PRTS_MASK) + 12);
+
+ /* Is the table big enough to contain this entry? */
+ if ((table_index * sizeof(entry)) >= size)
return -EINVAL;
- /* Read partition table to find root of tree for effective PID */
- ptbl = (kvm->arch.process_table & PRTB_MASK) + (pid * 16);
- ret = kvm_read_guest(kvm, ptbl, &prte, sizeof(prte));
+ /* Read the table to find the root of the radix tree */
+ ptbl = (table & PRTB_MASK) + (table_index * sizeof(entry));
+ ret = kvm_read_guest(kvm, ptbl, &entry, sizeof(entry));
if (ret)
return ret;
- root = be64_to_cpu(prte);
+ /* Root is stored in the first double word */
+ root = be64_to_cpu(entry.prtb0);
rts = ((root & RTS1_MASK) >> (RTS1_SHIFT - 3)) |
((root & RTS2_MASK) >> RTS2_SHIFT);
bits = root & RPDS_MASK;
- root = root & RPDB_MASK;
+ base = root & RPDB_MASK;
offset = rts + 31;
- /* current implementations only support 52-bit space */
+ /* Current implementations only support 52-bit space */
if (offset != 52)
return -EINVAL;
+ /* Walk each level of the radix tree */
for (level = 3; level >= 0; --level) {
+ /* Check a valid size */
if (level && bits != p9_supported_radix_bits[level])
return -EINVAL;
if (level == 0 && !(bits == 5 || bits == 9))
return -EINVAL;
offset -= bits;
index = (eaddr >> offset) & ((1UL << bits) - 1);
- /* check that low bits of page table base are zero */
- if (root & ((1UL << (bits + 3)) - 1))
+ /* Check that low bits of page table base are zero */
+ if (base & ((1UL << (bits + 3)) - 1))
return -EINVAL;
- ret = kvm_read_guest(kvm, root + index * 8,
+ /* Read the entry from guest memory */
+ ret = kvm_read_guest(kvm, base + (index * sizeof(rpte)),
&rpte, sizeof(rpte));
if (ret)
return ret;
pte = __be64_to_cpu(rpte);
if (!(pte & _PAGE_PRESENT))
return -ENOENT;
+ /* Check if a leaf entry */
if (pte & _PAGE_PTE)
break;
- bits = pte & 0x1f;
- root = pte & 0x0fffffffffffff00ul;
+ /* Get ready to walk the next level */
+ base = pte & RPDB_MASK;
+ bits = pte & RPDS_MASK;
}
- /* need a leaf at lowest level; 512GB pages not supported */
+
+ /* Need a leaf at lowest level; 512GB pages not supported */
if (level < 0 || level == 3)
return -EINVAL;
- /* offset is now log base 2 of the page size */
+ /* We found a valid leaf PTE */
+ /* Offset is now log base 2 of the page size */
gpa = pte & 0x01fffffffffff000ul;
if (gpa & ((1ul << offset) - 1))
return -EINVAL;
- gpa += eaddr & ((1ul << offset) - 1);
+ gpa |= eaddr & ((1ul << offset) - 1);
for (ps = MMU_PAGE_4K; ps < MMU_PAGE_COUNT; ++ps)
if (offset == mmu_psize_defs[ps].shift)
break;
@@ -118,6 +127,38 @@ int kvmppc_mmu_radix_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
gpte->may_read = !!(pte & _PAGE_READ);
gpte->may_write = !!(pte & _PAGE_WRITE);
gpte->may_execute = !!(pte & _PAGE_EXEC);
+
+ if (pte_ret_p)
+ *pte_ret_p = pte;
+
+ return 0;
+}
+
+int kvmppc_mmu_radix_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
+ struct kvmppc_pte *gpte, bool data, bool iswrite)
+{
+ u32 pid;
+ u64 pte;
+ int ret;
+
+ /* Work out effective PID */
+ switch (eaddr >> 62) {
+ case 0:
+ pid = vcpu->arch.pid;
+ break;
+ case 3:
+ pid = 0;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ ret = kvmppc_mmu_radix_translate_table(vcpu, eaddr, gpte,
+ vcpu->kvm->arch.process_table, pid, &pte);
+ if (ret)
+ return ret;
+
+ /* Check privilege (applies only to process scoped translations) */
if (kvmppc_get_msr(vcpu) & MSR_PR) {
if (pte & _PAGE_PRIVILEGED) {
gpte->may_read = 0;
--
2.7.4
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