On Tue, 31 Mar 2020 11:10:20 +0200
Cédric Le Goater <c...@kaod.org> wrote:
> On 3/30/20 7:00 PM, Greg Kurz wrote:
> > On Mon, 30 Mar 2020 11:49:44 +0200
> > Cédric Le Goater <c...@kaod.org> wrote:
> >
> >> The ppc_radix64_walk_tree() routine walks through the nested radix
> >> tables to look for a PTE.
> >>
> >> Split it two and introduce a new routine ppc_radix64_next_level()
> >
> > Split it in two...
> >
> >> which we will use for partition-scoped Radix translation when
> >> translating the process tree addresses.
> >>
> >> Signed-off-by: Suraj Jitindar Singh <sjitindarsi...@gmail.com>
> >> Signed-off-by: Cédric Le Goater <c...@kaod.org>
> >> ---
> >> target/ppc/mmu-radix64.c | 50 ++++++++++++++++++++++++++--------------
> >> 1 file changed, 33 insertions(+), 17 deletions(-)
> >>
> >> diff --git a/target/ppc/mmu-radix64.c b/target/ppc/mmu-radix64.c
> >> index b4e6abcd2d35..136498111f60 100644
> >> --- a/target/ppc/mmu-radix64.c
> >> +++ b/target/ppc/mmu-radix64.c
> >> @@ -162,44 +162,60 @@ static void ppc_radix64_set_rc(PowerPCCPU *cpu, int
> >> rwx, uint64_t pte,
> >> }
> >> }
> >>
> >> -static uint64_t ppc_radix64_walk_tree(PowerPCCPU *cpu, vaddr eaddr,
> >> - uint64_t base_addr, uint64_t nls,
> >> - hwaddr *raddr, int *psize,
> >> - int *fault_cause, hwaddr *pte_addr)
> >> +static uint64_t ppc_radix64_next_level(PowerPCCPU *cpu, vaddr eaddr,
> >> + uint64_t *pte_addr, uint64_t *nls,
> >> + int *psize, int *fault_cause)
> >> {
> >> CPUState *cs = CPU(cpu);
> >> uint64_t index, pde;
> >>
> >> - if (nls < 5) { /* Directory maps less than 2**5 entries */
> >> + if (*nls < 5) { /* Directory maps less than 2**5 entries */
> >> *fault_cause |= DSISR_R_BADCONFIG;
> >> return 0;
> >> }
> >>
> >
> > I think this should stay in the caller...
> >
> >> /* Read page <directory/table> entry from guest address space */
> >> - index = eaddr >> (*psize - nls); /* Shift */
> >> - index &= ((1UL << nls) - 1); /* Mask */
> >> - pde = ldq_phys(cs->as, base_addr + (index * sizeof(pde)));
> >> - if (!(pde & R_PTE_VALID)) { /* Invalid Entry */
> >> + pde = ldq_phys(cs->as, *pte_addr);
> >> + if (!(pde & R_PTE_VALID)) { /* Invalid Entry */
> >> *fault_cause |= DSISR_NOPTE;
> >> return 0;
> >> }
> >>
> >> - *psize -= nls;
> >> + *psize -= *nls;
> >> + if (!(pde & R_PTE_LEAF)) { /* Prepare for next iteration */
> >> + *nls = pde & R_PDE_NLS;
> >> + index = eaddr >> (*psize - *nls); /* Shift */
> >> + index &= ((1UL << *nls) - 1); /* Mask */
> >> + *pte_addr = (pde & R_PDE_NLB) + (index * sizeof(pde));
> >> + }
> >> + return pde;
> >> +}
> >> +
> >> +static uint64_t ppc_radix64_walk_tree(PowerPCCPU *cpu, vaddr eaddr,
> >> + uint64_t base_addr, uint64_t nls,
> >> + hwaddr *raddr, int *psize,
> >> + int *fault_cause, hwaddr *pte_addr)
> >> +{
> >> + uint64_t index, pde;
> >> +
> >> + index = eaddr >> (*psize - nls); /* Shift */
> >> + index &= ((1UL << nls) - 1); /* Mask */
> >> + *pte_addr = base_addr + (index * sizeof(pde));
> >> + do {
> >
> > ... here. So that we have a well established "bad config" path at
> > the root level, just like the current code has.
> >
> > Since the ppc_radix64_walk_tree() now calls ppc_radix64_next_level()
> > in a loop instead of recursing, and since ppc_radix64_next_level()
> > returns the nls value for the next level, it really makes sense to
> > have this check in ppc_radix64_walk_tree() and maybe put an assert
> > in ppc_radix64_next_level().
>
> ppc_radix64_next_level() also covers the needs of partition-scoped
> translation which translates each process table address. See PATCH 7.
>
> I rather not duplicate more code and leave it as it is.
>
These patches change the behaviour of some existing paths in a
non-trivial way. I'll wait for the respin and try to review again.
> Thanks,
>
> C.
>
> >
> >> + pde = ppc_radix64_next_level(cpu, eaddr, pte_addr, &nls, psize,
> >> + fault_cause);
> >> + } while ((pde & R_PTE_VALID) && !(pde & R_PTE_LEAF));
> >>
> >> - /* Check if Leaf Entry -> Page Table Entry -> Stop the Search */
> >> - if (pde & R_PTE_LEAF) {
> >> + /* Did we find a valid leaf? */
> >> + if ((pde & R_PTE_VALID) && (pde & R_PTE_LEAF)) {
> >> uint64_t rpn = pde & R_PTE_RPN;
> >> uint64_t mask = (1UL << *psize) - 1;
> >>
> >> /* Or high bits of rpn and low bits to ea to form whole real addr
> >> */
> >> *raddr = (rpn & ~mask) | (eaddr & mask);
> >> - *pte_addr = base_addr + (index * sizeof(pde));
> >> - return pde;
> >> }
> >>
> >> - /* Next Level of Radix Tree */
> >> - return ppc_radix64_walk_tree(cpu, eaddr, pde & R_PDE_NLB, pde &
> >> R_PDE_NLS,
> >> - raddr, psize, fault_cause, pte_addr);
> >> + return pde;
> >> }
> >>
> >> static bool validate_pate(PowerPCCPU *cpu, uint64_t lpid, ppc_v3_pate_t
> >> *pate)
> >
>
