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head/emulators/xen-kernel/files/xsa148-4.5.patch
| Property | Old Value | New Value |
|---|---|---|
| fbsd:nokeywords | null | yes \ No newline at end of property |
| x86: guard against undue super page PTE creation | |||||
| When optional super page support got added (commit bd1cd81d64 "x86: PV | |||||
| support for hugepages"), two adjustments were missed: mod_l2_entry() | |||||
| needs to consider the PSE and RW bits when deciding whether to use the | |||||
| fast path, and the PSE bit must not be removed from L2_DISALLOW_MASK | |||||
| unconditionally. | |||||
| This is XSA-148. | |||||
| Signed-off-by: Jan Beulich <jbeulich@suse.com> | |||||
| Reviewed-by: Tim Deegan <tim@xen.org> | |||||
| --- a/xen/arch/x86/mm.c | |||||
| +++ b/xen/arch/x86/mm.c | |||||
| @@ -162,7 +162,10 @@ static void put_superpage(unsigned long | |||||
| static uint32_t base_disallow_mask; | |||||
| /* Global bit is allowed to be set on L1 PTEs. Intended for user mappings. */ | |||||
| #define L1_DISALLOW_MASK ((base_disallow_mask | _PAGE_GNTTAB) & ~_PAGE_GLOBAL) | |||||
| -#define L2_DISALLOW_MASK (base_disallow_mask & ~_PAGE_PSE) | |||||
| + | |||||
| +#define L2_DISALLOW_MASK (unlikely(opt_allow_superpage) \ | |||||
| + ? base_disallow_mask & ~_PAGE_PSE \ | |||||
| + : base_disallow_mask) | |||||
| #define l3_disallow_mask(d) (!is_pv_32on64_domain(d) ? \ | |||||
| base_disallow_mask : \ | |||||
| @@ -1770,7 +1773,10 @@ static int mod_l2_entry(l2_pgentry_t *pl | |||||
| } | |||||
| /* Fast path for identical mapping and presence. */ | |||||
| - if ( !l2e_has_changed(ol2e, nl2e, _PAGE_PRESENT) ) | |||||
| + if ( !l2e_has_changed(ol2e, nl2e, | |||||
| + unlikely(opt_allow_superpage) | |||||
| + ? _PAGE_PSE | _PAGE_RW | _PAGE_PRESENT | |||||
| + : _PAGE_PRESENT) ) | |||||
| { | |||||
| adjust_guest_l2e(nl2e, d); | |||||
| if ( UPDATE_ENTRY(l2, pl2e, ol2e, nl2e, pfn, vcpu, preserve_ad) ) | |||||