Date: Mon, 22 Jun 2015 00:30:34 +0000 (UTC) From: Neel Natu <neel@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r284688 - head/lib/libvmmapi Message-ID: <201506220030.t5M0UYWf083614@svn.freebsd.org>
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Author: neel Date: Mon Jun 22 00:30:34 2015 New Revision: 284688 URL: https://svnweb.freebsd.org/changeset/base/284688 Log: Fix a regression in "movs" emulation after r284539. The regression was caused due to a change in behavior of the 'vm_map_gpa()'. Prior to r284539 if 'vm_map_gpa()' was called to map an address range in the guest MMIO region then it would return NULL. This was used by the "movs" emulation to detect if the 'src' or 'dst' operand was in MMIO space. Post r284539 'vm_map_gpa()' started returning a non-NULL pointer even when mapping the guest MMIO region. Fix this by returning non-NULL only if [gaddr, gaddr+len) is entirely within the 'lowmem' or 'highmem' regions and NULL otherwise. Pointy hat to: neel Reviewed by: grehan Reported by: tychon, Ben Perrault (ben.perrault@gmail.com) MFC after: 1 week Modified: head/lib/libvmmapi/vmmapi.c Modified: head/lib/libvmmapi/vmmapi.c ============================================================================== --- head/lib/libvmmapi/vmmapi.c Mon Jun 22 00:05:22 2015 (r284687) +++ head/lib/libvmmapi/vmmapi.c Mon Jun 22 00:30:34 2015 (r284688) @@ -415,19 +415,28 @@ vm_setup_memory(struct vmctx *ctx, size_ return (0); } +/* + * Returns a non-NULL pointer if [gaddr, gaddr+len) is entirely contained in + * the lowmem or highmem regions. + * + * In particular return NULL if [gaddr, gaddr+len) falls in guest MMIO region. + * The instruction emulation code depends on this behavior. + */ void * vm_map_gpa(struct vmctx *ctx, vm_paddr_t gaddr, size_t len) { - vm_paddr_t start, end, mapend; - start = gaddr; - end = gaddr + len; - mapend = ctx->highmem ? 4*GB + ctx->highmem : ctx->lowmem; + if (ctx->lowmem > 0) { + if (gaddr < ctx->lowmem && gaddr + len <= ctx->lowmem) + return (ctx->baseaddr + gaddr); + } - if (start <= end && end <= mapend) - return (ctx->baseaddr + start); - else - return (NULL); + if (ctx->highmem > 0) { + if (gaddr >= 4*GB && gaddr + len <= 4*GB + ctx->highmem) + return (ctx->baseaddr + gaddr); + } + + return (NULL); } size_t
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