On Fri, Sep 21, 2018 at 08:01:47PM +1000, Paul Mackerras wrote:
> From: Suraj Jitindar Singh <sjitindarsingh@xxxxxxxxx>
>
> 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@xxxxxxxxxx - reduced diffs from previous code]
>
> Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@xxxxxxxxx>
> Signed-off-by: Paul Mackerras <paulus@xxxxxxxxxx>
Reviewed-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> ---
> 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;
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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