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Re: [Qemu-ppc] [PATCH 1/3] ppc/hash64: Various fixes in PTE search in th
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From: |
Benjamin Herrenschmidt |
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Subject: |
Re: [Qemu-ppc] [PATCH 1/3] ppc/hash64: Various fixes in PTE search in the hash table |
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Date: |
Tue, 05 Jul 2016 07:18:54 +1000 |
On Mon, 2016-07-04 at 16:26 +0200, Cédric Le Goater wrote:
> On 07/04/2016 09:44 AM, Benjamin Herrenschmidt wrote:
> > We need to properly ignore different base size encodings,
> > since Linux might end up mixing them up. This also has the
> > advantage of speeding things up by no longer searching the
> > whole SPS array but only the sub-array for the SLB size.
> >
> > This includes some fixes by Cédric Le Goater <address@hidden>
> >
> > Signed-off-by: Benjamin Herrenschmidt <address@hidden>
>
>
> Ben,
>
> I can not apply these pathes on f3a161e3e2aa, David's branch ppc-for-
> 2.7 :/
Ah, David, you added "add proper real mode translation support" which I
rewrote in my series so it collides... can you drop it ?
Ben.
> C.
>
> > ---
> > hw/ppc/spapr_hcall.c | 8 +--
> > target-ppc/mmu-hash64.c | 172 +++++++++++++++++++-----------------
> > ------------
> > target-ppc/mmu-hash64.h | 5 +-
> > 3 files changed, 75 insertions(+), 110 deletions(-)
> >
> > diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> > index e011ed4..fe05078 100644
> > --- a/hw/ppc/spapr_hcall.c
> > +++ b/hw/ppc/spapr_hcall.c
> > @@ -83,18 +83,18 @@ static target_ulong h_enter(PowerPCCPU *cpu,
> > sPAPRMachineState *spapr,
> > target_ulong pte_index = args[1];
> > target_ulong pteh = args[2];
> > target_ulong ptel = args[3];
> > - unsigned apshift, spshift;
> > + unsigned pshift;
> > target_ulong raddr;
> > target_ulong index;
> > uint64_t token;
> >
> > - apshift = ppc_hash64_hpte_page_shift_noslb(cpu, pteh, ptel,
> > &spshift);
> > - if (!apshift) {
> > + pshift = ppc_hash64_hpte_page_shift_noslb(cpu, pteh, ptel);
> > + if (!pshift) {
> > /* Bad page size encoding */
> > return H_PARAMETER;
> > }
> >
> > - raddr = (ptel & HPTE64_R_RPN) & ~((1ULL << apshift) - 1);
> > + raddr = (ptel & HPTE64_R_RPN) & ~((1ULL << pshift) - 1);
> >
> > if (is_ram_address(spapr, raddr)) {
> > /* Regular RAM - should have WIMG=0010 */
> > diff --git a/target-ppc/mmu-hash64.c b/target-ppc/mmu-hash64.c
> > index 3b1357a..8a39295 100644
> > --- a/target-ppc/mmu-hash64.c
> > +++ b/target-ppc/mmu-hash64.c
> > @@ -450,37 +450,51 @@ void ppc_hash64_stop_access(PowerPCCPU *cpu,
> > uint64_t token)
> > }
> > }
> >
> > -/* Returns the effective page shift or 0. MPSS isn't supported yet
> > so
> > - * this will always be the slb_pshift or 0
> > - */
> > -static uint32_t ppc_hash64_pte_size_decode(uint64_t pte1, uint32_t
> > slb_pshift)
> > +
> > +static unsigned hpte_decode_psize(const struct
> > ppc_one_seg_page_size *sps,
> > + uint64_t pte0, uint64_t pte1)
> > {
> > - switch (slb_pshift) {
> > - case 12:
> > - return 12;
> > - case 16:
> > - if ((pte1 & 0xf000) == 0x1000) {
> > - return 16;
> > + int i;
> > +
> > + /* A 4K PTE is only valid on a 4K segment */
> > + if (!(pte0 & HPTE64_V_LARGE)) {
> > + return sps->page_shift == 12 ? 12 : 0;
> > + }
> > +
> > + /* Compare the PTE with the various encodings for the
> > + * segment base page size.
> > + */
> > + for (i = 0; i < PPC_PAGE_SIZES_MAX_SZ; i++) {
> > + const struct ppc_one_page_size *ps = &sps->enc[i];
> > + uint64_t mask;
> > +
> > + if (!ps->page_shift) {
> > + break;
> > }
> > - return 0;
> > - case 24:
> > - if ((pte1 & 0xff000) == 0) {
> > - return 24;
> > +
> > + if (ps->page_shift == 12) {
> > + /* L bit is set so this can't be a 4kiB page */
> > + continue;
> > + }
> > +
> > + mask = ((1ULL << ps->page_shift) - 1) & HPTE64_R_RPN;
> > +
> > + if ((pte1 & mask) == (ps->pte_enc << HPTE64_R_RPN_SHIFT))
> > {
> > + return ps->page_shift;
> > }
> > - return 0;
> > }
> > return 0;
> > }
> >
> > -static hwaddr ppc_hash64_pteg_search(PowerPCCPU *cpu, hwaddr hash,
> > - uint32_t slb_pshift, bool
> > secondary,
> > - target_ulong ptem,
> > ppc_hash_pte64_t *pte)
> > +static target_long ppc_hash64_pteg_search(PowerPCCPU *cpu, hwaddr
> > hash,
> > + ppc_slb_t *slb,
> > target_ulong ptem,
> > + ppc_hash_pte64_t *pte,
> > + unsigned *pshift)
> > {
> > CPUPPCState *env = &cpu->env;
> > - int i;
> > + target_ulong pte_index, pte0, pte1;
> > uint64_t token;
> > - target_ulong pte0, pte1;
> > - target_ulong pte_index;
> > + int i;
> >
> > pte_index = (hash & env->htab_mask) * HPTES_PER_GROUP;
> > token = ppc_hash64_start_access(cpu, pte_index);
> > @@ -489,18 +503,25 @@ static hwaddr
> > ppc_hash64_pteg_search(PowerPCCPU *cpu, hwaddr hash,
> > }
> > for (i = 0; i < HPTES_PER_GROUP; i++) {
> > pte0 = ppc_hash64_load_hpte0(cpu, token, i);
> > - pte1 = ppc_hash64_load_hpte1(cpu, token, i);
> >
> > - if ((pte0 & HPTE64_V_VALID)
> > - && (secondary == !!(pte0 & HPTE64_V_SECONDARY))
> > - && HPTE64_V_COMPARE(pte0, ptem)) {
> > - uint32_t pshift = ppc_hash64_pte_size_decode(pte1,
> > slb_pshift);
> > - if (pshift == 0) {
> > + /* This compares V, B, H (secondary) and the AVPN */
> > + if (HPTE64_V_COMPARE(pte0, ptem)) {
> > +
> > + /* Load the rest of the PTE */
> > + pte1 = ppc_hash64_load_hpte1(cpu, token, i);
> > +
> > + /* Decode the actual page size */
> > + *pshift = hpte_decode_psize(slb->sps, pte0, pte1);
> > +
> > + /* If there is no match, ignore the PTE, it could
> > simply be
> > + * for a different segment size encoding and the
> > architecture
> > + * specifies we should not match. Linux will
> > potentially leave
> > + * behind PTEs for the wrong base page size when
> > demoting
> > + * segments.
> > + */
> > + if ((*pshift) == 0) {
> > continue;
> > }
> > - /* We don't do anything with pshift yet as qemu TLB
> > only deals
> > - * with 4K pages anyway
> > - */
> > pte->pte0 = pte0;
> > pte->pte1 = pte1;
> > ppc_hash64_stop_access(cpu, token);
> > @@ -508,6 +529,7 @@ static hwaddr ppc_hash64_pteg_search(PowerPCCPU
> > *cpu, hwaddr hash,
> > }
> > }
> > ppc_hash64_stop_access(cpu, token);
> > +
> > /*
> > * We didn't find a valid entry.
> > */
> > @@ -516,7 +538,7 @@ static hwaddr ppc_hash64_pteg_search(PowerPCCPU
> > *cpu, hwaddr hash,
> >
> > static hwaddr ppc_hash64_htab_lookup(PowerPCCPU *cpu,
> > ppc_slb_t *slb, target_ulong
> > eaddr,
> > - ppc_hash_pte64_t *pte)
> > + ppc_hash_pte64_t *pte,
> > unsigned *pshift)
> > {
> > CPUPPCState *env = &cpu->env;
> > hwaddr pte_offset;
> > @@ -541,6 +563,7 @@ static hwaddr ppc_hash64_htab_lookup(PowerPCCPU
> > *cpu,
> > hash = vsid ^ (epn >> slb->sps->page_shift);
> > }
> > ptem = (slb->vsid & SLB_VSID_PTEM) | ((epn >> 16) &
> > HPTE64_V_AVPN);
> > + ptem |= HPTE64_V_VALID;
> >
> > /* Page address translation */
> > qemu_log_mask(CPU_LOG_MMU,
> > @@ -554,70 +577,33 @@ static hwaddr
> > ppc_hash64_htab_lookup(PowerPCCPU *cpu,
> > " vsid=" TARGET_FMT_lx " ptem=" TARGET_FMT_lx
> > " hash=" TARGET_FMT_plx "\n",
> > env->htab_base, env->htab_mask, vsid, ptem, hash);
> > - pte_offset = ppc_hash64_pteg_search(cpu, hash, slb->sps-
> > >page_shift,
> > - 0, ptem, pte);
> > + pte_offset = ppc_hash64_pteg_search(cpu, hash, slb,
> > + ptem, pte, pshift);
> >
> > if (pte_offset == -1) {
> > /* Secondary PTEG lookup */
> > + ptem |= HPTE64_V_SECONDARY;
> > qemu_log_mask(CPU_LOG_MMU,
> > "1 htab=" TARGET_FMT_plx "/" TARGET_FMT_plx
> > " vsid=" TARGET_FMT_lx " api=" TARGET_FMT_lx
> > " hash=" TARGET_FMT_plx "\n", env->htab_base,
> > env->htab_mask, vsid, ptem, ~hash);
> >
> > - pte_offset = ppc_hash64_pteg_search(cpu, ~hash, slb->sps-
> > >page_shift, 1,
> > - ptem, pte);
> > + pte_offset = ppc_hash64_pteg_search(cpu, ~hash, slb,
> > + ptem, pte, pshift);
> > }
> >
> > return pte_offset;
> > }
> >
> > -static unsigned hpte_page_shift(const struct ppc_one_seg_page_size
> > *sps,
> > - uint64_t pte0, uint64_t pte1)
> > -{
> > - int i;
> > -
> > - if (!(pte0 & HPTE64_V_LARGE)) {
> > - if (sps->page_shift != 12) {
> > - /* 4kiB page in a non 4kiB segment */
> > - return 0;
> > - }
> > - /* Normal 4kiB page */
> > - return 12;
> > - }
> > -
> > - for (i = 0; i < PPC_PAGE_SIZES_MAX_SZ; i++) {
> > - const struct ppc_one_page_size *ps = &sps->enc[i];
> > - uint64_t mask;
> > -
> > - if (!ps->page_shift) {
> > - break;
> > - }
> > -
> > - if (ps->page_shift == 12) {
> > - /* L bit is set so this can't be a 4kiB page */
> > - continue;
> > - }
> > -
> > - mask = ((1ULL << ps->page_shift) - 1) & HPTE64_R_RPN;
> > -
> > - if ((pte1 & mask) == (ps->pte_enc << HPTE64_R_RPN_SHIFT))
> > {
> > - return ps->page_shift;
> > - }
> > - }
> > -
> > - return 0; /* Bad page size encoding */
> > -}
> > -
> > +/* This is used by the H_ENTER implementation in hw/ppc/spapr.c */
> > unsigned ppc_hash64_hpte_page_shift_noslb(PowerPCCPU *cpu,
> > - uint64_t pte0, uint64_t
> > pte1,
> > - unsigned
> > *seg_page_shift)
> > + uint64_t pte0, uint64_t
> > pte1)
> > {
> > CPUPPCState *env = &cpu->env;
> > int i;
> >
> > if (!(pte0 & HPTE64_V_LARGE)) {
> > - *seg_page_shift = 12;
> > return 12;
> > }
> >
> > @@ -633,14 +619,11 @@ unsigned
> > ppc_hash64_hpte_page_shift_noslb(PowerPCCPU *cpu,
> > break;
> > }
> >
> > - shift = hpte_page_shift(sps, pte0, pte1);
> > + shift = hpte_decode_psize(sps, pte0, pte1);
> > if (shift) {
> > - *seg_page_shift = sps->page_shift;
> > return shift;
> > }
> > }
> > -
> > - *seg_page_shift = 0;
> > return 0;
> > }
> >
> > @@ -691,7 +674,7 @@ int ppc_hash64_handle_mmu_fault(PowerPCCPU
> > *cpu, vaddr eaddr,
> > CPUState *cs = CPU(cpu);
> > CPUPPCState *env = &cpu->env;
> > ppc_slb_t *slb;
> > - unsigned apshift;
> > + unsigned pshift;
> > hwaddr pte_offset;
> > ppc_hash_pte64_t pte;
> > int pp_prot, amr_prot, prot;
> > @@ -734,7 +717,7 @@ int ppc_hash64_handle_mmu_fault(PowerPCCPU
> > *cpu, vaddr eaddr,
> > }
> >
> > /* 4. Locate the PTE in the hash table */
> > - pte_offset = ppc_hash64_htab_lookup(cpu, slb, eaddr, &pte);
> > + pte_offset = ppc_hash64_htab_lookup(cpu, slb, eaddr, &pte,
> > &pshift);
> > if (pte_offset == -1) {
> > dsisr = 0x40000000;
> > if (rwx == 2) {
> > @@ -750,18 +733,6 @@ int ppc_hash64_handle_mmu_fault(PowerPCCPU
> > *cpu, vaddr eaddr,
> > qemu_log_mask(CPU_LOG_MMU,
> > "found PTE at offset %08" HWADDR_PRIx "\n",
> > pte_offset);
> >
> > - /* Validate page size encoding */
> > - apshift = hpte_page_shift(slb->sps, pte.pte0, pte.pte1);
> > - if (!apshift) {
> > - error_report("Bad page size encoding in HPTE 0x%"PRIx64" -
> > 0x%"PRIx64
> > - " @ 0x%"HWADDR_PRIx, pte.pte0, pte.pte1,
> > pte_offset);
> > - /* Not entirely sure what the right action here, but
> > machine
> > - * check seems reasonable */
> > - cs->exception_index = POWERPC_EXCP_MCHECK;
> > - env->error_code = 0;
> > - return 1;
> > - }
> > -
> > /* 5. Check access permissions */
> >
> > pp_prot = ppc_hash64_pte_prot(cpu, slb, pte);
> > @@ -809,10 +780,10 @@ int ppc_hash64_handle_mmu_fault(PowerPCCPU
> > *cpu, vaddr eaddr,
> >
> > /* 7. Determine the real address from the PTE */
> >
> > - raddr = deposit64(pte.pte1 & HPTE64_R_RPN, 0, apshift, eaddr);
> > + raddr = deposit64(pte.pte1 & HPTE64_R_RPN, 0, pshift, eaddr);
> >
> > tlb_set_page(cs, eaddr & TARGET_PAGE_MASK, raddr &
> > TARGET_PAGE_MASK,
> > - prot, mmu_idx, 1ULL << apshift);
> > + prot, mmu_idx, 1ULL << pshift);
> >
> > return 0;
> > }
> > @@ -823,7 +794,7 @@ hwaddr
> > ppc_hash64_get_phys_page_debug(PowerPCCPU *cpu, target_ulong addr)
> > ppc_slb_t *slb;
> > hwaddr pte_offset;
> > ppc_hash_pte64_t pte;
> > - unsigned apshift;
> > + unsigned pshift;
> >
> > if (msr_dr == 0) {
> > /* In real mode the top 4 effective address bits are
> > ignored */
> > @@ -835,17 +806,12 @@ hwaddr
> > ppc_hash64_get_phys_page_debug(PowerPCCPU *cpu, target_ulong addr)
> > return -1;
> > }
> >
> > - pte_offset = ppc_hash64_htab_lookup(cpu, slb, addr, &pte);
> > + pte_offset = ppc_hash64_htab_lookup(cpu, slb, addr, &pte,
> > &pshift);
> > if (pte_offset == -1) {
> > return -1;
> > }
> >
> > - apshift = hpte_page_shift(slb->sps, pte.pte0, pte.pte1);
> > - if (!apshift) {
> > - return -1;
> > - }
> > -
> > - return deposit64(pte.pte1 & HPTE64_R_RPN, 0, apshift, addr)
> > + return deposit64(pte.pte1 & HPTE64_R_RPN, 0, pshift, addr)
> > & TARGET_PAGE_MASK;
> > }
> >
> > diff --git a/target-ppc/mmu-hash64.h b/target-ppc/mmu-hash64.h
> > index 6423b9f..154a306 100644
> > --- a/target-ppc/mmu-hash64.h
> > +++ b/target-ppc/mmu-hash64.h
> > @@ -17,8 +17,7 @@ void ppc_hash64_tlb_flush_hpte(PowerPCCPU *cpu,
> > target_ulong pte_index,
> > target_ulong pte0, target_ulong
> > pte1);
> > unsigned ppc_hash64_hpte_page_shift_noslb(PowerPCCPU *cpu,
> > - uint64_t pte0, uint64_t
> > pte1,
> > - unsigned
> > *seg_page_shift);
> > + uint64_t pte0, uint64_t
> > pte1);
> > #endif
> >
> > /*
> > @@ -63,7 +62,7 @@ unsigned
> > ppc_hash64_hpte_page_shift_noslb(PowerPCCPU *cpu,
> > #define HPTE64_V_AVPN_SHIFT 7
> > #define HPTE64_V_AVPN 0x3fffffffffffff80ULL
> > #define HPTE64_V_AVPN_VAL(x) (((x) & HPTE64_V_AVPN) >>
> > HPTE64_V_AVPN_SHIFT)
> > -#define HPTE64_V_COMPARE(x, y) (!(((x) ^ (y)) &
> > 0xffffffffffffff80ULL))
> > +#define HPTE64_V_COMPARE(x, y) (!(((x) ^ (y)) &
> > 0xffffffffffffff83ULL))
> > #define HPTE64_V_LARGE 0x0000000000000004ULL
> > #define HPTE64_V_SECONDARY 0x0000000000000002ULL
> > #define HPTE64_V_VALID 0x0000000000000001ULL
> >