[Xen-devel] [PATCH v7 07/36] x86/mm: Don't use phys_to_virt in ioremap() if SME is active

[Tom Lendacky <thomas.lendacky@xxxxxxx>]

Currently there is a check if the address being mapped is in the ISA
range (is_ISA_range()), and if it is then phys_to_virt() is used to
perform the mapping.  When SME is active, however, this will result
in the mapping having the encryption bit set when it is expected that
an ioremap() should not have the encryption bit set. So only use the
phys_to_virt() function if SME is not active

Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
 arch/x86/mm/ioremap.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 4c1b5fd..a382ba9 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -13,6 +13,7 @@
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/mmiotrace.h>
+#include <linux/mem_encrypt.h>
 
 #include <asm/set_memory.h>
 #include <asm/e820/api.h>
@@ -106,9 +107,11 @@ static void __iomem *__ioremap_caller(resource_size_t 
phys_addr,
        }
 
        /*
-        * Don't remap the low PCI/ISA area, it's always mapped..
+        * Don't remap the low PCI/ISA area, it's always mapped.
+        *   But if SME is active, skip this so that the encryption bit
+        *   doesn't get set.
         */
-       if (is_ISA_range(phys_addr, last_addr))
+       if (is_ISA_range(phys_addr, last_addr) && !sme_active())
                return (__force void __iomem *)phys_to_virt(phys_addr);
 
        /*


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