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-rw-r--r--system/xen/patches/xsa173-4.6.patch244
1 files changed, 244 insertions, 0 deletions
diff --git a/system/xen/patches/xsa173-4.6.patch b/system/xen/patches/xsa173-4.6.patch
new file mode 100644
index 0000000000..aecf120c74
--- /dev/null
+++ b/system/xen/patches/xsa173-4.6.patch
@@ -0,0 +1,244 @@
+commit 54a4651cb4e744960fb375ed99909d7dfb943caf
+Author: Tim Deegan <tim@xen.org>
+Date: Wed Mar 16 16:51:27 2016 +0000
+
+ x86: limit GFNs to 32 bits for shadowed superpages.
+
+ Superpage shadows store the shadowed GFN in the backpointer field,
+ which for non-BIGMEM builds is 32 bits wide. Shadowing a superpage
+ mapping of a guest-physical address above 2^44 would lead to the GFN
+ being truncated there, and a crash when we come to remove the shadow
+ from the hash table.
+
+ Track the valid width of a GFN for each guest, including reporting it
+ through CPUID, and enforce it in the shadow pagetables. Set the
+ maximum witth to 32 for guests where this truncation could occur.
+
+ This is XSA-173.
+
+ Signed-off-by: Tim Deegan <tim@xen.org>
+ Signed-off-by: Jan Beulich <jbeulich@suse.com>
+
+Reported-by: Ling Liu <liuling-it@360.cn>
+diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
+index 35ef21b..528c283 100644
+--- a/xen/arch/x86/cpu/common.c
++++ b/xen/arch/x86/cpu/common.c
+@@ -38,6 +38,7 @@ integer_param("cpuid_mask_ext_edx", opt_cpuid_mask_ext_edx);
+ const struct cpu_dev *__read_mostly cpu_devs[X86_VENDOR_NUM] = {};
+
+ unsigned int paddr_bits __read_mostly = 36;
++unsigned int hap_paddr_bits __read_mostly = 36;
+
+ /*
+ * Default host IA32_CR_PAT value to cover all memory types.
+@@ -211,7 +212,7 @@ static void __init early_cpu_detect(void)
+
+ static void __cpuinit generic_identify(struct cpuinfo_x86 *c)
+ {
+- u32 tfms, capability, excap, ebx;
++ u32 tfms, capability, excap, ebx, eax;
+
+ /* Get vendor name */
+ cpuid(0x00000000, &c->cpuid_level,
+@@ -248,8 +249,11 @@ static void __cpuinit generic_identify(struct cpuinfo_x86 *c)
+ }
+ if ( c->extended_cpuid_level >= 0x80000004 )
+ get_model_name(c); /* Default name */
+- if ( c->extended_cpuid_level >= 0x80000008 )
+- paddr_bits = cpuid_eax(0x80000008) & 0xff;
++ if ( c->extended_cpuid_level >= 0x80000008 ) {
++ eax = cpuid_eax(0x80000008);
++ paddr_bits = eax & 0xff;
++ hap_paddr_bits = ((eax >> 16) & 0xff) ?: paddr_bits;
++ }
+ }
+
+ /* Might lift BIOS max_leaf=3 limit. */
+diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
+index e200aab..0b4d9f0 100644
+--- a/xen/arch/x86/hvm/hvm.c
++++ b/xen/arch/x86/hvm/hvm.c
+@@ -4567,8 +4567,7 @@ void hvm_cpuid(unsigned int input, unsigned int *eax, unsigned int *ebx,
+ break;
+
+ case 0x80000008:
+- count = cpuid_eax(0x80000008);
+- count = (count >> 16) & 0xff ?: count & 0xff;
++ count = d->arch.paging.gfn_bits + PAGE_SHIFT;
+ if ( (*eax & 0xff) > count )
+ *eax = (*eax & ~0xff) | count;
+
+diff --git a/xen/arch/x86/mm/guest_walk.c b/xen/arch/x86/mm/guest_walk.c
+index 773454d..06543d3 100644
+--- a/xen/arch/x86/mm/guest_walk.c
++++ b/xen/arch/x86/mm/guest_walk.c
+@@ -93,6 +93,12 @@ void *map_domain_gfn(struct p2m_domain *p2m, gfn_t gfn, mfn_t *mfn,
+ struct page_info *page;
+ void *map;
+
++ if ( gfn_x(gfn) >> p2m->domain->arch.paging.gfn_bits )
++ {
++ *rc = _PAGE_INVALID_BIT;
++ return NULL;
++ }
++
+ /* Translate the gfn, unsharing if shared */
+ page = get_page_from_gfn_p2m(p2m->domain, p2m, gfn_x(gfn), p2mt, NULL,
+ q);
+@@ -326,20 +332,8 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m,
+ flags &= ~_PAGE_PAT;
+
+ if ( gfn_x(start) & GUEST_L2_GFN_MASK & ~0x1 )
+- {
+-#if GUEST_PAGING_LEVELS == 2
+- /*
+- * Note that _PAGE_INVALID_BITS is zero in this case, yielding a
+- * no-op here.
+- *
+- * Architecturally, the walk should fail if bit 21 is set (others
+- * aren't being checked at least in PSE36 mode), but we'll ignore
+- * this here in order to avoid specifying a non-natural, non-zero
+- * _PAGE_INVALID_BITS value just for that case.
+- */
+-#endif
+ rc |= _PAGE_INVALID_BITS;
+- }
++
+ /* Increment the pfn by the right number of 4k pages.
+ * Mask out PAT and invalid bits. */
+ start = _gfn((gfn_x(start) & ~GUEST_L2_GFN_MASK) +
+@@ -422,5 +416,11 @@ set_ad:
+ put_page(mfn_to_page(mfn_x(gw->l1mfn)));
+ }
+
++ /* If this guest has a restricted physical address space then the
++ * target GFN must fit within it. */
++ if ( !(rc & _PAGE_PRESENT)
++ && gfn_x(guest_l1e_get_gfn(gw->l1e)) >> d->arch.paging.gfn_bits )
++ rc |= _PAGE_INVALID_BITS;
++
+ return rc;
+ }
+diff --git a/xen/arch/x86/mm/hap/hap.c b/xen/arch/x86/mm/hap/hap.c
+index 6eb2167..f3475c6 100644
+--- a/xen/arch/x86/mm/hap/hap.c
++++ b/xen/arch/x86/mm/hap/hap.c
+@@ -448,6 +448,8 @@ void hap_domain_init(struct domain *d)
+ {
+ INIT_PAGE_LIST_HEAD(&d->arch.paging.hap.freelist);
+
++ d->arch.paging.gfn_bits = hap_paddr_bits - PAGE_SHIFT;
++
+ /* Use HAP logdirty mechanism. */
+ paging_log_dirty_init(d, hap_enable_log_dirty,
+ hap_disable_log_dirty,
+diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
+index bad8360..98d0d2c 100644
+--- a/xen/arch/x86/mm/shadow/common.c
++++ b/xen/arch/x86/mm/shadow/common.c
+@@ -51,6 +51,16 @@ int shadow_domain_init(struct domain *d, unsigned int domcr_flags)
+ INIT_PAGE_LIST_HEAD(&d->arch.paging.shadow.freelist);
+ INIT_PAGE_LIST_HEAD(&d->arch.paging.shadow.pinned_shadows);
+
++ d->arch.paging.gfn_bits = paddr_bits - PAGE_SHIFT;
++#ifndef CONFIG_BIGMEM
++ /*
++ * Shadowed superpages store GFNs in 32-bit page_info fields.
++ * Note that we cannot use guest_supports_superpages() here.
++ */
++ if ( !is_pv_domain(d) || opt_allow_superpage )
++ d->arch.paging.gfn_bits = 32;
++#endif
++
+ /* Use shadow pagetables for log-dirty support */
+ paging_log_dirty_init(d, sh_enable_log_dirty,
+ sh_disable_log_dirty, sh_clean_dirty_bitmap);
+diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
+index 43c9488..71477fe 100644
+--- a/xen/arch/x86/mm/shadow/multi.c
++++ b/xen/arch/x86/mm/shadow/multi.c
+@@ -525,7 +525,8 @@ _sh_propagate(struct vcpu *v,
+ ASSERT(GUEST_PAGING_LEVELS > 3 || level != 3);
+
+ /* Check there's something for the shadows to map to */
+- if ( !p2m_is_valid(p2mt) && !p2m_is_grant(p2mt) )
++ if ( (!p2m_is_valid(p2mt) && !p2m_is_grant(p2mt))
++ || gfn_x(target_gfn) >> d->arch.paging.gfn_bits )
+ {
+ *sp = shadow_l1e_empty();
+ goto done;
+diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
+index c6c6e71..74c3a52 100644
+--- a/xen/include/asm-x86/domain.h
++++ b/xen/include/asm-x86/domain.h
+@@ -193,6 +193,9 @@ struct paging_domain {
+ /* log dirty support */
+ struct log_dirty_domain log_dirty;
+
++ /* Number of valid bits in a gfn. */
++ unsigned int gfn_bits;
++
+ /* preemption handling */
+ struct {
+ const struct domain *dom;
+diff --git a/xen/include/asm-x86/guest_pt.h b/xen/include/asm-x86/guest_pt.h
+index f8a0d76..b5db401 100644
+--- a/xen/include/asm-x86/guest_pt.h
++++ b/xen/include/asm-x86/guest_pt.h
+@@ -210,15 +210,17 @@ guest_supports_nx(struct vcpu *v)
+ }
+
+
+-/* Some bits are invalid in any pagetable entry. */
+-#if GUEST_PAGING_LEVELS == 2
+-#define _PAGE_INVALID_BITS (0)
+-#elif GUEST_PAGING_LEVELS == 3
+-#define _PAGE_INVALID_BITS \
+- get_pte_flags(((1ull<<63) - 1) & ~((1ull<<paddr_bits) - 1))
+-#else /* GUEST_PAGING_LEVELS == 4 */
++/*
++ * Some bits are invalid in any pagetable entry.
++ * Normal flags values get represented in 24-bit values (see
++ * get_pte_flags() and put_pte_flags()), so set bit 24 in
++ * addition to be able to flag out of range frame numbers.
++ */
++#if GUEST_PAGING_LEVELS == 3
+ #define _PAGE_INVALID_BITS \
+- get_pte_flags(((1ull<<52) - 1) & ~((1ull<<paddr_bits) - 1))
++ (_PAGE_INVALID_BIT | get_pte_flags(((1ull << 63) - 1) & ~(PAGE_SIZE - 1)))
++#else /* 2-level and 4-level */
++#define _PAGE_INVALID_BITS _PAGE_INVALID_BIT
+ #endif
+
+
+diff --git a/xen/include/asm-x86/processor.h b/xen/include/asm-x86/processor.h
+index f507f5e..a200470 100644
+--- a/xen/include/asm-x86/processor.h
++++ b/xen/include/asm-x86/processor.h
+@@ -212,6 +212,8 @@ extern u32 cpuid_ext_features;
+
+ /* Maximum width of physical addresses supported by the hardware */
+ extern unsigned int paddr_bits;
++/* Max physical address width supported within HAP guests */
++extern unsigned int hap_paddr_bits;
+
+ extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id table[]);
+
+diff --git a/xen/include/asm-x86/x86_64/page.h b/xen/include/asm-x86/x86_64/page.h
+index 19ab4d0..eb5e2fd 100644
+--- a/xen/include/asm-x86/x86_64/page.h
++++ b/xen/include/asm-x86/x86_64/page.h
+@@ -141,6 +141,12 @@ typedef l4_pgentry_t root_pgentry_t;
+ #define _PAGE_GNTTAB (1U<<22)
+
+ /*
++ * Bit 24 of a 24-bit flag mask! This is not any bit of a real pte,
++ * and is only used for signalling in variables that contain flags.
++ */
++#define _PAGE_INVALID_BIT (1U<<24)
++
++/*
+ * Bit 12 of a 24-bit flag mask. This corresponds to bit 52 of a pte.
+ * This is needed to distinguish between user and kernel PTEs since _PAGE_USER
+ * is asserted for both.
generated by cgit v1.2.3 (git 2.26.2) at 2024-06-30 19:35:35 +0000