From ed6c77ebf0c1f865b45596c3e793fe87160251a6 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Wed, 22 Sep 2021 16:14:19 +0200 Subject: [PATCH] AMD/IOMMU: check / convert IVMD ranges for being / to be reserved While the specification doesn't say so, just like for VT-d's RMRRs no good can come from these ranges being e.g. conventional RAM or entirely unmarked and hence usable for placing e.g. PCI device BARs. Check whether they are, and put in some limited effort to convert to reserved. (More advanced logic can be added if actual problems are found with this simplistic variant.) Signed-off-by: Jan Beulich Reviewed-by: Paul Durrant --- xen/drivers/passthrough/amd/iommu_acpi.c | 32 ++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/xen/drivers/passthrough/amd/iommu_acpi.c b/xen/drivers/passthrough/amd/iommu_acpi.c index 2fdebd2d74..bc3c946fe5 100644 --- a/xen/drivers/passthrough/amd/iommu_acpi.c +++ b/xen/drivers/passthrough/amd/iommu_acpi.c @@ -384,6 +384,38 @@ static int __init parse_ivmd_block(const struct acpi_ivrs_memory *ivmd_block) AMD_IOMMU_DEBUG("IVMD Block: type %#x phys %#lx len %#lx\n", ivmd_block->header.type, start_addr, mem_length); + if ( !e820_all_mapped(base, limit + PAGE_SIZE, E820_RESERVED) ) + { + paddr_t addr; + + AMD_IOMMU_DEBUG("IVMD: [%lx,%lx) is not (entirely) in reserved memory\n", + base, limit + PAGE_SIZE); + + for ( addr = base; addr <= limit; addr += PAGE_SIZE ) + { + unsigned int type = page_get_ram_type(maddr_to_mfn(addr)); + + if ( type == RAM_TYPE_UNKNOWN ) + { + if ( e820_add_range(&e820, addr, addr + PAGE_SIZE, + E820_RESERVED) ) + continue; + AMD_IOMMU_DEBUG("IVMD Error: Page at %lx couldn't be reserved\n", + addr); + return -EIO; + } + + /* Types which won't be handed out are considered good enough. */ + if ( !(type & (RAM_TYPE_RESERVED | RAM_TYPE_ACPI | + RAM_TYPE_UNUSABLE)) ) + continue; + + AMD_IOMMU_DEBUG("IVMD Error: Page at %lx can't be converted\n", + addr); + return -EIO; + } + } + if ( ivmd_block->header.flags & ACPI_IVMD_EXCLUSION_RANGE ) exclusion = true; else if ( ivmd_block->header.flags & ACPI_IVMD_UNITY ) -- 2.30.2