diff options
Diffstat (limited to 'system/xen/patches/xsa154-4.6.patch')
| -rw-r--r-- | system/xen/patches/xsa154-4.6.patch | 359 |
1 files changed, 0 insertions, 359 deletions
diff --git a/system/xen/patches/xsa154-4.6.patch b/system/xen/patches/xsa154-4.6.patch deleted file mode 100644 index f1e598812bac..000000000000 --- a/system/xen/patches/xsa154-4.6.patch +++ /dev/null @@ -1,359 +0,0 @@ -x86: enforce consistent cachability of MMIO mappings - -We've been told by Intel that inconsistent cachability between -multiple mappings of the same page can affect system stability only -when the affected page is an MMIO one. Since the stale data issue is -of no relevance to the hypervisor (since all guest memory accesses go -through proper accessors and validation), handling of RAM pages -remains unchanged here. Any MMIO mapped by domains however needs to be -done consistently (all cachable mappings or all uncachable ones), in -order to avoid Machine Check exceptions. Since converting existing -cachable mappings to uncachable (at the time an uncachable mapping -gets established) would in the PV case require tracking all mappings, -allow MMIO to only get mapped uncachable (UC, UC-, or WC). - -This also implies that in the PV case we mustn't use the L1 PTE update -fast path when cachability flags get altered. - -Since in the HVM case at least for now we want to continue honoring -pinned cachability attributes for pages not mapped by the hypervisor, -special case handling of r/o MMIO pages (forcing UC) gets added there. -Arguably the counterpart change to p2m-pt.c may not be necessary, since -UC- (which already gets enforced there) is probably strict enough. - -Note that the shadow code changes include fixing the write protection -of r/o MMIO ranges: shadow_l1e_remove_flags() and its siblings, other -than l1e_remove_flags() and alike, return the new PTE (and hence -ignoring their return values makes them no-ops). - -This is CVE-2016-2270 / XSA-154. - -Signed-off-by: Jan Beulich <jbeulich@suse.com> -Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> - ---- a/docs/misc/xen-command-line.markdown -+++ b/docs/misc/xen-command-line.markdown -@@ -1080,6 +1080,15 @@ limit is ignored by Xen. - - Specify if the MMConfig space should be enabled. - -+### mmio-relax -+> `= <boolean> | all` -+ -+> Default: `false` -+ -+By default, domains may not create cached mappings to MMIO regions. -+This option relaxes the check for Domain 0 (or when using `all`, all PV -+domains), to permit the use of cacheable MMIO mappings. -+ - ### msi - > `= <boolean>` - ---- a/xen/arch/x86/hvm/mtrr.c -+++ b/xen/arch/x86/hvm/mtrr.c -@@ -807,8 +807,17 @@ int epte_get_entry_emt(struct domain *d, - if ( v->domain != d ) - v = d->vcpu ? d->vcpu[0] : NULL; - -- if ( !mfn_valid(mfn_x(mfn)) ) -+ if ( !mfn_valid(mfn_x(mfn)) || -+ rangeset_contains_range(mmio_ro_ranges, mfn_x(mfn), -+ mfn_x(mfn) + (1UL << order) - 1) ) -+ { -+ *ipat = 1; - return MTRR_TYPE_UNCACHABLE; -+ } -+ -+ if ( rangeset_overlaps_range(mmio_ro_ranges, mfn_x(mfn), -+ mfn_x(mfn) + (1UL << order) - 1) ) -+ return -1; - - switch ( hvm_get_mem_pinned_cacheattr(d, gfn, order, &type) ) - { ---- a/xen/arch/x86/mm/p2m-pt.c -+++ b/xen/arch/x86/mm/p2m-pt.c -@@ -107,6 +107,8 @@ static unsigned long p2m_type_to_flags(p - case p2m_mmio_direct: - if ( !rangeset_contains_singleton(mmio_ro_ranges, mfn_x(mfn)) ) - flags |= _PAGE_RW; -+ else -+ flags |= _PAGE_PWT; - return flags | P2M_BASE_FLAGS | _PAGE_PCD; - } - } ---- a/xen/arch/x86/mm/shadow/multi.c -+++ b/xen/arch/x86/mm/shadow/multi.c -@@ -519,6 +519,7 @@ _sh_propagate(struct vcpu *v, - gfn_t target_gfn = guest_l1e_get_gfn(guest_entry); - u32 pass_thru_flags; - u32 gflags, sflags; -+ bool_t mmio_mfn; - - /* We don't shadow PAE l3s */ - ASSERT(GUEST_PAGING_LEVELS > 3 || level != 3); -@@ -559,7 +560,10 @@ _sh_propagate(struct vcpu *v, - // mfn means that we can not usefully shadow anything, and so we - // return early. - // -- if ( !mfn_valid(target_mfn) -+ mmio_mfn = !mfn_valid(target_mfn) -+ || (level == 1 -+ && page_get_owner(mfn_to_page(target_mfn)) == dom_io); -+ if ( mmio_mfn - && !(level == 1 && (!shadow_mode_refcounts(d) - || p2mt == p2m_mmio_direct)) ) - { -@@ -577,7 +581,7 @@ _sh_propagate(struct vcpu *v, - _PAGE_RW | _PAGE_PRESENT); - if ( guest_supports_nx(v) ) - pass_thru_flags |= _PAGE_NX_BIT; -- if ( !shadow_mode_refcounts(d) && !mfn_valid(target_mfn) ) -+ if ( level == 1 && !shadow_mode_refcounts(d) && mmio_mfn ) - pass_thru_flags |= _PAGE_PAT | _PAGE_PCD | _PAGE_PWT; - sflags = gflags & pass_thru_flags; - -@@ -676,10 +680,14 @@ _sh_propagate(struct vcpu *v, - } - - /* Read-only memory */ -- if ( p2m_is_readonly(p2mt) || -- (p2mt == p2m_mmio_direct && -- rangeset_contains_singleton(mmio_ro_ranges, mfn_x(target_mfn))) ) -+ if ( p2m_is_readonly(p2mt) ) - sflags &= ~_PAGE_RW; -+ else if ( p2mt == p2m_mmio_direct && -+ rangeset_contains_singleton(mmio_ro_ranges, mfn_x(target_mfn)) ) -+ { -+ sflags &= ~(_PAGE_RW | _PAGE_PAT); -+ sflags |= _PAGE_PCD | _PAGE_PWT; -+ } - - // protect guest page tables - // -@@ -1185,22 +1193,28 @@ static int shadow_set_l1e(struct domain - && !sh_l1e_is_magic(new_sl1e) ) - { - /* About to install a new reference */ -- if ( shadow_mode_refcounts(d) ) { -+ if ( shadow_mode_refcounts(d) ) -+ { -+#define PAGE_FLIPPABLE (_PAGE_RW | _PAGE_PWT | _PAGE_PCD | _PAGE_PAT) -+ int rc; -+ - TRACE_SHADOW_PATH_FLAG(TRCE_SFLAG_SHADOW_L1_GET_REF); -- switch ( shadow_get_page_from_l1e(new_sl1e, d, new_type) ) -+ switch ( rc = shadow_get_page_from_l1e(new_sl1e, d, new_type) ) - { - default: - /* Doesn't look like a pagetable. */ - flags |= SHADOW_SET_ERROR; - new_sl1e = shadow_l1e_empty(); - break; -- case 1: -- shadow_l1e_remove_flags(new_sl1e, _PAGE_RW); -+ case PAGE_FLIPPABLE & -PAGE_FLIPPABLE ... PAGE_FLIPPABLE: -+ ASSERT(!(rc & ~PAGE_FLIPPABLE)); -+ new_sl1e = shadow_l1e_flip_flags(new_sl1e, rc); - /* fall through */ - case 0: - shadow_vram_get_l1e(new_sl1e, sl1e, sl1mfn, d); - break; - } -+#undef PAGE_FLIPPABLE - } - } - ---- a/xen/arch/x86/mm/shadow/types.h -+++ b/xen/arch/x86/mm/shadow/types.h -@@ -99,6 +99,9 @@ static inline u32 shadow_l4e_get_flags(s - static inline shadow_l1e_t - shadow_l1e_remove_flags(shadow_l1e_t sl1e, u32 flags) - { l1e_remove_flags(sl1e, flags); return sl1e; } -+static inline shadow_l1e_t -+shadow_l1e_flip_flags(shadow_l1e_t sl1e, u32 flags) -+{ l1e_flip_flags(sl1e, flags); return sl1e; } - - static inline shadow_l1e_t shadow_l1e_empty(void) - { return l1e_empty(); } ---- a/xen/arch/x86/mm.c -+++ b/xen/arch/x86/mm.c -@@ -178,6 +178,18 @@ static uint32_t base_disallow_mask; - is_pv_domain(d)) ? \ - L1_DISALLOW_MASK : (L1_DISALLOW_MASK & ~PAGE_CACHE_ATTRS)) - -+static s8 __read_mostly opt_mmio_relax; -+static void __init parse_mmio_relax(const char *s) -+{ -+ if ( !*s ) -+ opt_mmio_relax = 1; -+ else -+ opt_mmio_relax = parse_bool(s); -+ if ( opt_mmio_relax < 0 && strcmp(s, "all") ) -+ opt_mmio_relax = 0; -+} -+custom_param("mmio-relax", parse_mmio_relax); -+ - static void __init init_frametable_chunk(void *start, void *end) - { - unsigned long s = (unsigned long)start; -@@ -799,10 +811,7 @@ get_page_from_l1e( - if ( !mfn_valid(mfn) || - (real_pg_owner = page_get_owner_and_reference(page)) == dom_io ) - { --#ifndef NDEBUG -- const unsigned long *ro_map; -- unsigned int seg, bdf; --#endif -+ int flip = 0; - - /* Only needed the reference to confirm dom_io ownership. */ - if ( mfn_valid(mfn) ) -@@ -836,24 +845,55 @@ get_page_from_l1e( - return -EINVAL; - } - -- if ( !(l1f & _PAGE_RW) || -- !rangeset_contains_singleton(mmio_ro_ranges, mfn) ) -- return 0; -+ if ( !rangeset_contains_singleton(mmio_ro_ranges, mfn) ) -+ { -+ /* MMIO pages must not be mapped cachable unless requested so. */ -+ switch ( opt_mmio_relax ) -+ { -+ case 0: -+ break; -+ case 1: -+ if ( is_hardware_domain(l1e_owner) ) -+ case -1: -+ return 0; -+ default: -+ ASSERT_UNREACHABLE(); -+ } -+ } -+ else if ( l1f & _PAGE_RW ) -+ { - #ifndef NDEBUG -- if ( !pci_mmcfg_decode(mfn, &seg, &bdf) || -- ((ro_map = pci_get_ro_map(seg)) != NULL && -- test_bit(bdf, ro_map)) ) -- printk(XENLOG_G_WARNING -- "d%d: Forcing read-only access to MFN %lx\n", -- l1e_owner->domain_id, mfn); -- else -- rangeset_report_ranges(mmio_ro_ranges, 0, ~0UL, -- print_mmio_emul_range, -- &(struct mmio_emul_range_ctxt){ -- .d = l1e_owner, -- .mfn = mfn }); -+ const unsigned long *ro_map; -+ unsigned int seg, bdf; -+ -+ if ( !pci_mmcfg_decode(mfn, &seg, &bdf) || -+ ((ro_map = pci_get_ro_map(seg)) != NULL && -+ test_bit(bdf, ro_map)) ) -+ printk(XENLOG_G_WARNING -+ "d%d: Forcing read-only access to MFN %lx\n", -+ l1e_owner->domain_id, mfn); -+ else -+ rangeset_report_ranges(mmio_ro_ranges, 0, ~0UL, -+ print_mmio_emul_range, -+ &(struct mmio_emul_range_ctxt){ -+ .d = l1e_owner, -+ .mfn = mfn }); - #endif -- return 1; -+ flip = _PAGE_RW; -+ } -+ -+ switch ( l1f & PAGE_CACHE_ATTRS ) -+ { -+ case 0: /* WB */ -+ flip |= _PAGE_PWT | _PAGE_PCD; -+ break; -+ case _PAGE_PWT: /* WT */ -+ case _PAGE_PWT | _PAGE_PAT: /* WP */ -+ flip |= _PAGE_PCD | (l1f & _PAGE_PAT); -+ break; -+ } -+ -+ return flip; - } - - if ( unlikely( (real_pg_owner != pg_owner) && -@@ -1243,8 +1283,9 @@ static int alloc_l1_table(struct page_in - goto fail; - case 0: - break; -- case 1: -- l1e_remove_flags(pl1e[i], _PAGE_RW); -+ case _PAGE_RW ... _PAGE_RW | PAGE_CACHE_ATTRS: -+ ASSERT(!(ret & ~(_PAGE_RW | PAGE_CACHE_ATTRS))); -+ l1e_flip_flags(pl1e[i], ret); - break; - } - -@@ -1759,8 +1800,9 @@ static int mod_l1_entry(l1_pgentry_t *pl - return -EINVAL; - } - -- /* Fast path for identical mapping, r/w and presence. */ -- if ( !l1e_has_changed(ol1e, nl1e, _PAGE_RW | _PAGE_PRESENT) ) -+ /* Fast path for identical mapping, r/w, presence, and cachability. */ -+ if ( !l1e_has_changed(ol1e, nl1e, -+ PAGE_CACHE_ATTRS | _PAGE_RW | _PAGE_PRESENT) ) - { - adjust_guest_l1e(nl1e, pt_dom); - if ( UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, gl1mfn, pt_vcpu, -@@ -1783,8 +1825,9 @@ static int mod_l1_entry(l1_pgentry_t *pl - return rc; - case 0: - break; -- case 1: -- l1e_remove_flags(nl1e, _PAGE_RW); -+ case _PAGE_RW ... _PAGE_RW | PAGE_CACHE_ATTRS: -+ ASSERT(!(rc & ~(_PAGE_RW | PAGE_CACHE_ATTRS))); -+ l1e_flip_flags(nl1e, rc); - rc = 0; - break; - } -@@ -5000,6 +5043,7 @@ static int ptwr_emulated_update( - l1_pgentry_t pte, ol1e, nl1e, *pl1e; - struct vcpu *v = current; - struct domain *d = v->domain; -+ int ret; - - /* Only allow naturally-aligned stores within the original %cr2 page. */ - if ( unlikely(((addr^ptwr_ctxt->cr2) & PAGE_MASK) || (addr & (bytes-1))) ) -@@ -5047,7 +5091,7 @@ static int ptwr_emulated_update( - - /* Check the new PTE. */ - nl1e = l1e_from_intpte(val); -- switch ( get_page_from_l1e(nl1e, d, d) ) -+ switch ( ret = get_page_from_l1e(nl1e, d, d) ) - { - default: - if ( is_pv_32bit_domain(d) && (bytes == 4) && (unaligned_addr & 4) && -@@ -5071,8 +5115,9 @@ static int ptwr_emulated_update( - break; - case 0: - break; -- case 1: -- l1e_remove_flags(nl1e, _PAGE_RW); -+ case _PAGE_RW ... _PAGE_RW | PAGE_CACHE_ATTRS: -+ ASSERT(!(ret & ~(_PAGE_RW | PAGE_CACHE_ATTRS))); -+ l1e_flip_flags(nl1e, ret); - break; - } - ---- a/xen/include/asm-x86/page.h -+++ b/xen/include/asm-x86/page.h -@@ -157,6 +157,9 @@ static inline l4_pgentry_t l4e_from_padd - #define l3e_remove_flags(x, flags) ((x).l3 &= ~put_pte_flags(flags)) - #define l4e_remove_flags(x, flags) ((x).l4 &= ~put_pte_flags(flags)) - -+/* Flip flags in an existing L1 PTE. */ -+#define l1e_flip_flags(x, flags) ((x).l1 ^= put_pte_flags(flags)) -+ - /* Check if a pte's page mapping or significant access flags have changed. */ - #define l1e_has_changed(x,y,flags) \ - ( !!(((x).l1 ^ (y).l1) & ((PADDR_MASK&PAGE_MASK)|put_pte_flags(flags))) ) |