Thread (66 messages) 66 messages, 10 authors, 2022-11-30

Re: [Patch v3 01/14] x86/ioremap: Fix page aligned size calculation in __ioremap_caller()

From: Borislav Petkov <bp@alien8.de>
Date: 2022-11-21 13:33:15
Also in: linux-arch, linux-hyperv, linux-iommu, linux-pci, lkml

On Wed, Nov 16, 2022 at 10:41:24AM -0800, Michael Kelley wrote:
quoted hunk ↗ jump to hunk
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.

Signed-off-by: Michael Kelley <redacted>
---
 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 @@ static void __ioremap_check_mem(resource_size_t 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) {
-- 
This looks like a fix to me that needs to go to independently to stable.
And it would need a Fixes tag.

/me does some git archeology...

I guess this one:

ffa71f33a820 ("x86, ioremap: Fix incorrect physical address handling in PAE mode")

should be old enough so that it goes to all relevant stable kernels...

Hmm?

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette
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