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 <andrew.coop...@citrix.com>
---
CC: Jan Beulich <jbeul...@suse.com>
CC: Wei Liu <wei.l...@citrix.com>
CC: Roger Pau Monné <roger....@citrix.com>
---
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 727dad4..8d0f6f1 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
--
2.1.4
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