Date: Tue, 18 Mar 2014 16:20:34 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r263305 - head/sys/x86/iommu Message-ID: <201403181620.s2IGKYGa029467@svn.freebsd.org>
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Author: kib Date: Tue Mar 18 16:20:33 2014 New Revision: 263305 URL: http://svnweb.freebsd.org/changeset/base/263305 Log: It is not uncommon for BIOSes to report wrong RMRR entries in DMAR table. Among them, some (old AMI ?) BIOSes report entries with range like (bf7ec000, bf7ebfff). Attempts to ignore the bogus entries result in faults, so the range must be covered somehow. Provide a workaround by identity mapping the 32 pages after the bogus entry start, which seems to be enough for the reported BIOS. Reported and tested by: Jason Harmening <jason.harmening@gmail.com> Sponsored by: The FreeBSD Foundation MFC after: 1 week Modified: head/sys/x86/iommu/intel_ctx.c Modified: head/sys/x86/iommu/intel_ctx.c ============================================================================== --- head/sys/x86/iommu/intel_ctx.c Tue Mar 18 15:59:06 2014 (r263304) +++ head/sys/x86/iommu/intel_ctx.c Tue Mar 18 16:20:33 2014 (r263305) @@ -182,6 +182,15 @@ ctx_init_rmrr(struct dmar_ctx *ctx, devi end = entry->end; entry->start = trunc_page(start); entry->end = round_page(end); + if (entry->start == entry->end) { + /* Workaround for some AMI (?) BIOSes */ + if (bootverbose) { + device_printf(dev, "BIOS bug: dmar%d RMRR " + "region (%jx, %jx) corrected\n", + ctx->dmar->unit, start, end); + } + entry->end += DMAR_PAGE_SIZE * 0x20; + } size = OFF_TO_IDX(entry->end - entry->start); ma = malloc(sizeof(vm_page_t) * size, M_TEMP, M_WAITOK); for (i = 0; i < size; i++) {
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