From 828e114f7cdd9910483783ab0563b178325e579a Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Thu, 21 Jan 2016 16:09:22 +0100 Subject: [PATCH] x86/mmuext: tighten TLB flush address checks Addresses passed by PV guests should be subjected to __addr_ok(), avoiding undue TLB flushes. Signed-off-by: Jan Beulich Reviewed-by: Andrew Cooper --- xen/arch/x86/mm.c | 13 +++++++------ xen/include/asm-x86/paging.h | 4 +++- 2 files changed, 10 insertions(+), 7 deletions(-) diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c index b81d1fdcdf..b5d0ebc380 100644 --- a/xen/arch/x86/mm.c +++ b/xen/arch/x86/mm.c @@ -3268,8 +3268,9 @@ long do_mmuext_op( case MMUEXT_INVLPG_LOCAL: if ( unlikely(d != pg_owner) ) rc = -EPERM; - else if ( !paging_mode_enabled(d) || - paging_invlpg(curr, op.arg1.linear_addr) != 0 ) + else if ( !paging_mode_enabled(d) + ? __addr_ok(op.arg1.linear_addr) + : paging_invlpg(curr, op.arg1.linear_addr) ) flush_tlb_one_local(op.arg1.linear_addr); break; @@ -3290,7 +3291,7 @@ long do_mmuext_op( if ( op.cmd == MMUEXT_TLB_FLUSH_MULTI ) flush_tlb_mask(&pmask); - else + else if ( __addr_ok(op.arg1.linear_addr) ) flush_tlb_one_mask(&pmask, op.arg1.linear_addr); break; } @@ -3303,10 +3304,10 @@ long do_mmuext_op( break; case MMUEXT_INVLPG_ALL: - if ( likely(d == pg_owner) ) - flush_tlb_one_mask(d->domain_dirty_cpumask, op.arg1.linear_addr); - else + if ( unlikely(d != pg_owner) ) rc = -EPERM; + else if ( __addr_ok(op.arg1.linear_addr) ) + flush_tlb_one_mask(d->domain_dirty_cpumask, op.arg1.linear_addr); break; case MMUEXT_FLUSH_CACHE: diff --git a/xen/include/asm-x86/paging.h b/xen/include/asm-x86/paging.h index 6215f57ebc..c4129530a6 100644 --- a/xen/include/asm-x86/paging.h +++ b/xen/include/asm-x86/paging.h @@ -245,7 +245,9 @@ paging_fault(unsigned long va, struct cpu_user_regs *regs) * or 0 if it's safe not to do so. */ static inline int paging_invlpg(struct vcpu *v, unsigned long va) { - return is_canonical_address(va) && paging_get_hostmode(v)->invlpg(v, va); + return (paging_mode_external(v->domain) ? is_canonical_address(va) + : __addr_ok(va)) && + paging_get_hostmode(v)->invlpg(v, va); } /* Translate a guest virtual address to the frame number that the -- 2.30.2