[tip: x86/urgent] x86/ioremap: Fix page aligned size calculation in __ioremap_caller()

[tip-bot2 for Michael Kelley]

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     4dbd6a3e90e03130973688fd79e19425f720d999
Gitweb:        https://git.kernel.org/tip/4dbd6a3e90e03130973688fd79e19425f720d999
Author:        Michael Kelley <mikelley@xxxxxxxxxxxxx>
AuthorDate:    Wed, 16 Nov 2022 10:41:24 -08:00
Committer:     Borislav Petkov <bp@xxxxxxx>
CommitterDate: Tue, 22 Nov 2022 12:21:16 +01:00

x86/ioremap: Fix page aligned size calculation in __ioremap_caller()

Current code re-calculates the size after aligning the starting and
ending physical addresses on a page boundary. But the re-calculation
also embeds the masking of high order bits that exceed the size of
the physical address space (via PHYSICAL_PAGE_MASK). If the masking
removes any high order bits, the size calculation results in a huge
value that is likely to immediately fail.

Fix this by re-calculating the page-aligned size first. Then mask any
high order bits using PHYSICAL_PAGE_MASK.

Fixes: ffa71f33a820 ("x86, ioremap: Fix incorrect physical address handling in PAE mode")
Signed-off-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Acked-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Link: https://lore.kernel.org/r/1668624097-14884-2-git-send-email-mikelley@xxxxxxxxxxxxx
---
 arch/x86/mm/ioremap.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 78c5bc6..6453fba 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -217,9 +217,15 @@ __ioremap_caller(resource_size_t phys_addr, unsigned long size,
 	 * Mappings have to be page-aligned
 	 */
 	offset = phys_addr & ~PAGE_MASK;
-	phys_addr &= PHYSICAL_PAGE_MASK;
+	phys_addr &= PAGE_MASK;
 	size = PAGE_ALIGN(last_addr+1) - phys_addr;
 
+	/*
+	 * Mask out any bits not part of the actual physical
+	 * address, like memory encryption bits.
+	 */
+	phys_addr &= PHYSICAL_PAGE_MASK;
+
 	retval = memtype_reserve(phys_addr, (u64)phys_addr + size,
 						pcm, &new_pcm);
 	if (retval) {