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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] RE: [Xen-changelog] [PAE] Allow pgdirs above 4GB for paravirt guests.
Keir, Dom0 hangs with this patch when loading modules. If I back it out, it boots fine. I configured dom0 as SMP (and the machine has >4GB). Jun --- Intel Open Source Technology Center -----Original Message----- From: xen-changelog-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-changelog-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Xen patchbot-unstable Sent: Friday, May 26, 2006 11:48 AM To: xen-changelog@xxxxxxxxxxxxxxxxxxx Subject: [Xen-changelog] [PAE] Allow pgdirs above 4GB for paravirt guests. # HG changeset patch # User kaf24@xxxxxxxxxxxxxxxxxxxx # Node ID 954f4dea9da6336aaa35d0706aed55fde7909644 # Parent 3ed325fa395bb75f846b29bd3fa571ffc03eb5e4 [PAE] Allow pgdirs above 4GB for paravirt guests. **NOTE**: This obviates the need for lowmem_emergency_pool. Unpriv guests no longer need to be able to allocate memory below 4GB for PAE PDPTs. Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx> --- tools/libxc/xc_linux_build.c | 13 ---- tools/libxc/xc_linux_restore.c | 122 +++-------------------------------------- tools/libxc/xc_private.c | 22 ------- tools/libxc/xenctrl.h | 3 - xen/arch/x86/domain_build.c | 5 + xen/arch/x86/mm.c | 98 ++++++++++++++++++++++++++++---- xen/common/kernel.c | 5 - xen/include/asm-x86/domain.h | 12 ++++ 8 files changed, 113 insertions(+), 167 deletions(-) diff -r 3ed325fa395b -r 954f4dea9da6 tools/libxc/xc_linux_build.c --- a/tools/libxc/xc_linux_build.c Fri May 26 13:53:49 2006 +0100 +++ b/tools/libxc/xc_linux_build.c Fri May 26 17:22:30 2006 +0100 @@ -268,21 +268,10 @@ static int setup_pg_tables_pae(int xc_ha l2_pgentry_64_t *vl2tab = NULL, *vl2e = NULL; l3_pgentry_64_t *vl3tab = NULL, *vl3e = NULL; uint64_t l1tab, l2tab, l3tab, pl1tab, pl2tab, pl3tab; - unsigned long ppt_alloc, count, nmfn; + unsigned long ppt_alloc, count; /* First allocate page for page dir. */ ppt_alloc = (vpt_start - dsi_v_start) >> PAGE_SHIFT; - - if ( page_array[ppt_alloc] > 0xfffff ) - { - nmfn = xc_make_page_below_4G(xc_handle, dom, page_array[ppt_alloc]); - if ( nmfn == 0 ) - { - fprintf(stderr, "Couldn't get a page below 4GB :-(\n"); - goto error_out; - } - page_array[ppt_alloc] = nmfn; - } alloc_pt(l3tab, vl3tab, pl3tab); vl3e = &vl3tab[l3_table_offset_pae(dsi_v_start)]; diff -r 3ed325fa395b -r 954f4dea9da6 tools/libxc/xc_linux_restore.c --- a/tools/libxc/xc_linux_restore.c Fri May 26 13:53:49 2006 +0100 +++ b/tools/libxc/xc_linux_restore.c Fri May 26 17:22:30 2006 +0100 @@ -331,25 +331,17 @@ int xc_linux_restore(int xc_handle, int ** A page table page - need to 'uncanonicalize' it, i.e. ** replace all the references to pfns with the corresponding ** mfns for the new domain. - ** - ** On PAE we need to ensure that PGDs are in MFNs < 4G, and - ** so we may need to update the p2m after the main loop. - ** Hence we defer canonicalization of L1s until then. */ - if(pt_levels != 3 || pagetype != L1TAB) { - - if(!uncanonicalize_pagetable(pagetype, page)) { - /* - ** Failing to uncanonicalize a page table can be ok - ** under live migration since the pages type may have - ** changed by now (and we'll get an update later). - */ - DPRINTF("PT L%ld race on pfn=%08lx mfn=%08lx\n", - pagetype >> 28, pfn, mfn); - nraces++; - continue; - } - + if(!uncanonicalize_pagetable(pagetype, page)) { + /* + ** Failing to uncanonicalize a page table can be ok + ** under live migration since the pages type may have + ** changed by now (and we'll get an update later). + */ + DPRINTF("PT L%ld race on pfn=%08lx mfn=%08lx\n", + pagetype >> 28, pfn, mfn); + nraces++; + continue; } } else if(pagetype != NOTAB) { @@ -397,100 +389,6 @@ int xc_linux_restore(int xc_handle, int } DPRINTF("Received all pages (%d races)\n", nraces); - - if(pt_levels == 3) { - - /* - ** XXX SMH on PAE we need to ensure PGDs are in MFNs < 4G. This - ** is a little awkward and involves (a) finding all such PGDs and - ** replacing them with 'lowmem' versions; (b) upating the p2m[] - ** with the new info; and (c) canonicalizing all the L1s using the - ** (potentially updated) p2m[]. - ** - ** This is relatively slow (and currently involves two passes through - ** the pfn_type[] array), but at least seems to be correct. May wish - ** to consider more complex approaches to optimize this later. - */ - - int j, k; - - /* First pass: find all L3TABs current in > 4G mfns and get new mfns */ - for (i = 0; i < max_pfn; i++) { - - if (((pfn_type[i] & LTABTYPE_MASK)==L3TAB) && (p2m[i]>0xfffffUL)) { - - unsigned long new_mfn; - uint64_t l3ptes[4]; - uint64_t *l3tab; - - l3tab = (uint64_t *) - xc_map_foreign_range(xc_handle, dom, PAGE_SIZE, - PROT_READ, p2m[i]); - - for(j = 0; j < 4; j++) - l3ptes[j] = l3tab[j]; - - munmap(l3tab, PAGE_SIZE); - - if (!(new_mfn=xc_make_page_below_4G(xc_handle, dom, p2m[i]))) { - ERR("Couldn't get a page below 4GB :-("); - goto out; - } - - p2m[i] = new_mfn; - if (xc_add_mmu_update(xc_handle, mmu, - (((unsigned long long)new_mfn) - << PAGE_SHIFT) | - MMU_MACHPHYS_UPDATE, i)) { - ERR("Couldn't m2p on PAE root pgdir"); - goto out; - } - - l3tab = (uint64_t *) - xc_map_foreign_range(xc_handle, dom, PAGE_SIZE, - PROT_READ | PROT_WRITE, p2m[i]); - - for(j = 0; j < 4; j++) - l3tab[j] = l3ptes[j]; - - munmap(l3tab, PAGE_SIZE); - - } - } - - /* Second pass: find all L1TABs and uncanonicalize them */ - j = 0; - - for(i = 0; i < max_pfn; i++) { - - if (((pfn_type[i] & LTABTYPE_MASK)==L1TAB)) { - region_mfn[j] = p2m[i]; - j++; - } - - if(i == (max_pfn-1) || j == MAX_BATCH_SIZE) { - - if (!(region_base = xc_map_foreign_batch( - xc_handle, dom, PROT_READ | PROT_WRITE, - region_mfn, j))) { - ERR("map batch failed"); - goto out; - } - - for(k = 0; k < j; k++) { - if(!uncanonicalize_pagetable(L1TAB, - region_base + k*PAGE_SIZE)) { - ERR("failed uncanonicalize pt!"); - goto out; - } - } - - munmap(region_base, j*PAGE_SIZE); - j = 0; - } - } - - } if (xc_finish_mmu_updates(xc_handle, mmu)) { diff -r 3ed325fa395b -r 954f4dea9da6 tools/libxc/xc_private.c --- a/tools/libxc/xc_private.c Fri May 26 13:53:49 2006 +0100 +++ b/tools/libxc/xc_private.c Fri May 26 17:22:30 2006 +0100 @@ -430,28 +430,6 @@ int xc_version(int xc_handle, int cmd, v return rc; } -unsigned long xc_make_page_below_4G( - int xc_handle, uint32_t domid, unsigned long mfn) -{ - unsigned long new_mfn; - - if ( xc_domain_memory_decrease_reservation( - xc_handle, domid, 1, 0, &mfn) != 0 ) - { - fprintf(stderr,"xc_make_page_below_4G decrease failed. mfn=%lx\n",mfn); - return 0; - } - - if ( xc_domain_memory_increase_reservation( - xc_handle, domid, 1, 0, 32, &new_mfn) != 0 ) - { - fprintf(stderr,"xc_make_page_below_4G increase failed. mfn=%lx\n",mfn); - return 0; - } - - return new_mfn; -} - /* * Local variables: * mode: C diff -r 3ed325fa395b -r 954f4dea9da6 tools/libxc/xenctrl.h --- a/tools/libxc/xenctrl.h Fri May 26 13:53:49 2006 +0100 +++ b/tools/libxc/xenctrl.h Fri May 26 17:22:30 2006 +0100 @@ -453,9 +453,6 @@ int xc_domain_iomem_permission(int xc_ha unsigned long nr_mfns, uint8_t allow_access); -unsigned long xc_make_page_below_4G(int xc_handle, uint32_t domid, - unsigned long mfn); - typedef dom0_perfc_desc_t xc_perfc_desc_t; /* IMPORTANT: The caller is responsible for mlock()'ing the @desc array. */ int xc_perfc_control(int xc_handle, diff -r 3ed325fa395b -r 954f4dea9da6 xen/arch/x86/domain_build.c --- a/xen/arch/x86/domain_build.c Fri May 26 13:53:49 2006 +0100 +++ b/xen/arch/x86/domain_build.c Fri May 26 17:22:30 2006 +0100 @@ -367,7 +367,10 @@ int construct_dom0(struct domain *d, if ( (1UL << order) > nr_pages ) panic("Domain 0 allocation is too small for kernel image.\n"); - /* Allocate from DMA pool: PAE L3 table must be below 4GB boundary. */ + /* + * Allocate from DMA pool: on i386 this ensures that our low-memory 1:1 + * mapping covers the allocation. + */ if ( (page = alloc_domheap_pages(d, order, ALLOC_DOM_DMA)) == NULL ) panic("Not enough RAM for domain 0 allocation.\n"); alloc_spfn = page_to_mfn(page); diff -r 3ed325fa395b -r 954f4dea9da6 xen/arch/x86/mm.c --- a/xen/arch/x86/mm.c Fri May 26 13:53:49 2006 +0100 +++ b/xen/arch/x86/mm.c Fri May 26 17:22:30 2006 +0100 @@ -260,9 +260,42 @@ void share_xen_page_with_privileged_gues share_xen_page_with_guest(page, dom_xen, readonly); } +static void __write_ptbase(unsigned long mfn) +{ +#ifdef CONFIG_X86_PAE + if ( mfn >= 0x100000 ) + { + l3_pgentry_t *highmem_l3tab, *lowmem_l3tab; + struct vcpu *v = current; + unsigned long flags; + + /* Protects against re-entry and against __pae_flush_pgd(). */ + local_irq_save(flags); + + /* Pick an unused low-memory L3 cache slot. */ + v->arch.lowmem_l3tab_inuse ^= 1; + lowmem_l3tab = v->arch.lowmem_l3tab[v->arch.lowmem_l3tab_inuse]; + v->arch.lowmem_l3tab_high_mfn[v->arch.lowmem_l3tab_inuse] = mfn; + + /* Map the guest L3 table and copy to the chosen low-memory cache. */ + highmem_l3tab = map_domain_page(mfn); + memcpy(lowmem_l3tab, highmem_l3tab, sizeof(v->arch.lowmem_l3tab)); + unmap_domain_page(highmem_l3tab); + + /* Install the low-memory L3 table in CR3. */ + write_cr3(__pa(lowmem_l3tab)); + + local_irq_restore(flags); + return; + } +#endif + + write_cr3(mfn << PAGE_SHIFT); +} + void write_ptbase(struct vcpu *v) { - write_cr3(pagetable_get_paddr(v->arch.monitor_table)); + __write_ptbase(pagetable_get_pfn(v->arch.monitor_table)); } void invalidate_shadow_ldt(struct vcpu *v) @@ -401,6 +434,7 @@ static int get_page_and_type_from_pagenr return 1; } +#ifndef CONFIG_X86_PAE /* We do not support guest linear mappings on PAE. */ /* * We allow root tables to map each other (a.k.a. linear page tables). It * needs some special care with reference counts and access permissions: @@ -456,6 +490,7 @@ get_linear_pagetable( return 1; } +#endif /* !CONFIG_X86_PAE */ int get_page_from_l1e( @@ -564,10 +599,6 @@ get_page_from_l3e( rc = get_page_and_type_from_pagenr( l3e_get_pfn(l3e), PGT_l2_page_table | vaddr, d); -#if CONFIG_PAGING_LEVELS == 3 - if ( unlikely(!rc) ) - rc = get_linear_pagetable(l3e, pfn, d); -#endif return rc; } #endif /* 3 level */ @@ -773,6 +804,50 @@ static int create_pae_xen_mappings(l3_pg return 1; } +struct pae_flush_pgd { + unsigned long l3tab_mfn; + unsigned int l3tab_idx; + l3_pgentry_t nl3e; +}; + +static void __pae_flush_pgd(void *data) +{ + struct pae_flush_pgd *args = data; + struct vcpu *v = this_cpu(curr_vcpu); + int i = v->arch.lowmem_l3tab_inuse; + intpte_t _ol3e, _nl3e, _pl3e; + l3_pgentry_t *l3tab_ptr; + + ASSERT(!local_irq_is_enabled()); + + if ( v->arch.lowmem_l3tab_high_mfn[i] != args->l3tab_mfn ) + return; + + l3tab_ptr = &v->arch.lowmem_l3tab[i][args->l3tab_idx]; + + _ol3e = l3e_get_intpte(*l3tab_ptr); + _nl3e = l3e_get_intpte(args->nl3e); + _pl3e = cmpxchg((intpte_t *)l3tab_ptr, _ol3e, _nl3e); + BUG_ON(_pl3e != _ol3e); +} + +/* Flush a pgdir update into low-memory caches. */ +static void pae_flush_pgd( + unsigned long mfn, unsigned int idx, l3_pgentry_t nl3e) +{ + struct domain *d = page_get_owner(mfn_to_page(mfn)); + struct pae_flush_pgd args = { + .l3tab_mfn = mfn, + .l3tab_idx = idx, + .nl3e = nl3e }; + + /* If below 4GB then the pgdir is not shadowed in low memory. */ + if ( mfn < 0x100000 ) + return; + + on_selected_cpus(d->domain_dirty_cpumask, __pae_flush_pgd, &args, 1, 1); +} + static inline int l1_backptr( unsigned long *backptr, unsigned long offset_in_l2, unsigned long l2_type) { @@ -787,6 +862,7 @@ static inline int l1_backptr( #elif CONFIG_X86_64 # define create_pae_xen_mappings(pl3e) (1) +# define pae_flush_pgd(mfn, idx, nl3e) ((void)0) static inline int l1_backptr( unsigned long *backptr, unsigned long offset_in_l2, unsigned long l2_type) @@ -886,14 +962,6 @@ static int alloc_l3_table(struct page_in ASSERT(!shadow_mode_refcounts(d)); -#ifdef CONFIG_X86_PAE - if ( pfn >= 0x100000 ) - { - MEM_LOG("PAE pgd must be below 4GB (0x%lx >= 0x100000)", pfn); - return 0; - } -#endif - pl3e = map_domain_page(pfn); for ( i = 0; i < L3_PAGETABLE_ENTRIES; i++ ) { @@ -1240,6 +1308,8 @@ static int mod_l3_entry(l3_pgentry_t *pl okay = create_pae_xen_mappings(pl3e); BUG_ON(!okay); + + pae_flush_pgd(pfn, pgentry_ptr_to_slot(pl3e), nl3e); put_page_from_l3e(ol3e, pfn); return 1; @@ -3109,7 +3179,7 @@ void ptwr_flush(struct domain *d, const if ( unlikely(d->arch.ptwr[which].vcpu != current) ) /* Don't use write_ptbase: it may switch to guest_user on x86/64! */ - write_cr3(pagetable_get_paddr( + __write_ptbase(pagetable_get_pfn( d->arch.ptwr[which].vcpu->arch.guest_table)); else TOGGLE_MODE(); diff -r 3ed325fa395b -r 954f4dea9da6 xen/common/kernel.c --- a/xen/common/kernel.c Fri May 26 13:53:49 2006 +0100 +++ b/xen/common/kernel.c Fri May 26 17:22:30 2006 +0100 @@ -191,12 +191,11 @@ long do_xen_version(int cmd, XEN_GUEST_H switch ( fi.submap_idx ) { case 0: - fi.submap = 0; + fi.submap = (1U << XENFEAT_pae_pgdir_above_4gb); if ( shadow_mode_translate(current->domain) ) fi.submap |= (1U << XENFEAT_writable_page_tables) | - (1U << XENFEAT_auto_translated_physmap) | - (1U << XENFEAT_pae_pgdir_above_4gb); + (1U << XENFEAT_auto_translated_physmap); if ( supervisor_mode_kernel ) fi.submap |= 1U << XENFEAT_supervisor_mode_kernel; break; diff -r 3ed325fa395b -r 954f4dea9da6 xen/include/asm-x86/domain.h --- a/xen/include/asm-x86/domain.h Fri May 26 13:53:49 2006 +0100 +++ b/xen/include/asm-x86/domain.h Fri May 26 17:22:30 2006 +0100 @@ -120,6 +120,18 @@ struct arch_vcpu struct vcpu_guest_context guest_context __attribute__((__aligned__(16))); +#ifdef CONFIG_X86_PAE + /* + * Two low-memory (<4GB) PAE L3 tables, used as fallback when the guest + * supplies a >=4GB PAE L3 table. We need two because we cannot set up + * an L3 table while we are currently running on it (without using + * expensive atomic 64-bit operations). + */ + l3_pgentry_t lowmem_l3tab[2][4] __attribute__((__aligned__(32))); + unsigned long lowmem_l3tab_high_mfn[2]; /* The >=4GB MFN being shadowed. */ + unsigned int lowmem_l3tab_inuse; /* Which lowmem_l3tab is in use? */ +#endif + unsigned long flags; /* TF_ */ void (*schedule_tail) (struct vcpu *); _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-changelog _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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