[PATCH v4 1/1] x86/ioremap: Fix page aligned size calculation in __ioremap_caller()

[PATCH v4 1/1] x86/ioremap: Fix page aligned size calculation in __ioremap_caller()

[Michael Kelley]

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")
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
---

This patch was previously Patch 1 of a larger series[1].  Breaking
it out separately per discussion with Dave Hansen and Boris Petkov.

[1] https://lore.kernel.org/linux-hyperv/1668624097-14884-1-git-send-email-mikelley@microsoft.com/

 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) {
-- 
1.8.3.1

Re: [PATCH v4 1/1] x86/ioremap: Fix page aligned size calculation in __ioremap_caller()

[Wei Liu]

On Tue, Nov 22, 2022 at 09:40:42AM -0800, Michael Kelley wrote:
> 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")
> Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
> Signed-off-by: Michael Kelley <mikelley@microsoft.com>

Reviewed-by: Wei Liu <wei.liu@kernel.org>

> ---
> 
> This patch was previously Patch 1 of a larger series[1].  Breaking
> it out separately per discussion with Dave Hansen and Boris Petkov.
> 
> [1] https://lore.kernel.org/linux-hyperv/1668624097-14884-1-git-send-email-mikelley@microsoft.com/
> 
>  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) {
> -- 
> 1.8.3.1
> 

RE: [PATCH v4 1/1] x86/ioremap: Fix page aligned size calculation in __ioremap_caller()

[Michael Kelley (LINUX)]

From: Wei Liu <wei.liu@kernel.org> Sent: Friday, November 25, 2022 7:20 AM
> 
> On Tue, Nov 22, 2022 at 09:40:42AM -0800, Michael Kelley wrote:
> > 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")
> > Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
> > Signed-off-by: Michael Kelley <mikelley@microsoft.com>
> 
> Reviewed-by: Wei Liu <wei.liu@kernel.org>
> 
> > ---
> >
> > This patch was previously Patch 1 of a larger series[1].  Breaking
> > it out separately per discussion with Dave Hansen and Boris Petkov.
> >
> > [1] https://lore.kernel.org/linux-hyperv/1668624097-14884-1-git-send-email-mikelley@microsoft.com/
> >

Boris -- you were going to pick up this patch separately
though urgent.  Can you go ahead and do that?

https://lore.kernel.org/linux-hyperv/Y3vo5drAFPQSsrF4@zn.tnic/

Michael

> >  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) {
> > --
> > 1.8.3.1
> >

Re: [PATCH v4 1/1] x86/ioremap: Fix page aligned size calculation in __ioremap_caller()

[Borislav Petkov]

On Mon, Nov 28, 2022 at 02:43:28PM +0000, Michael Kelley (LINUX) wrote:
> Boris -- you were going to pick up this patch separately
> though urgent.  Can you go ahead and do that?

Did you not get the tip-bot notification?

https://lore.kernel.org/r/166911713030.4906.16935727667401525991.tip-bot2@tip-bot2

you're on Cc there too.

-- 
Regards/Gruss,
    Boris.

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

RE: [PATCH v4 1/1] x86/ioremap: Fix page aligned size calculation in __ioremap_caller()

[Michael Kelley (LINUX)]

From: Borislav Petkov <bp@alien8.de> Sent: Monday, November 28, 2022 7:46 AM
> 
> On Mon, Nov 28, 2022 at 02:43:28PM +0000, Michael Kelley (LINUX) wrote:
> > Boris -- you were going to pick up this patch separately
> > though urgent.  Can you go ahead and do that?
> 
> Did you not get the tip-bot notification?
> 
> https://lore.kernel.org/all/166911713030.4906.16935727667401525991.tip-bot2@tip-bot2/
> 
> you're on Cc there too.
> 

Argh.  My mistake.  Thanks.

Michael