From 3e4ec07e14bce81f6ae22c31ff1302d1f297a226 Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Thu, 16 Aug 2018 16:26:22 +0100 Subject: [PATCH] x86/setup: Avoid OoB E820 lookup when calculating the L1TF safe address MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit A number of corner cases (most obviously, no-real-mode and no Multiboot memory map) can end up with e820_raw.nr_map being 0, at which point the L1TF calculation will underflow. Spotted by Coverity. Signed-off-by: Andrew Cooper Reviewed-by: Roger Pau Monné Reviewed-by: Jan Beulich Reviewed-by: Wei Liu --- xen/arch/x86/setup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c index 727dad4dc3..8d0f6f14e3 100644 --- a/xen/arch/x86/setup.c +++ b/xen/arch/x86/setup.c @@ -913,7 +913,7 @@ void __init noreturn __start_xen(unsigned long mbi_p) /* Sanitise the raw E820 map to produce a final clean version. */ max_page = raw_max_page = init_e820(memmap_type, &e820_raw); - if ( !efi_enabled(EFI_BOOT) ) + if ( !efi_enabled(EFI_BOOT) && e820_raw.nr_map >= 1 ) { /* * Supplement the heuristics in l1tf_calculations() by assuming that -- 2.30.2