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* [PATCH v2 0/2] iommu/vt-d bad RMRR workarounds
@ 2020-01-07 19:16 ` Barret Rhoden via iommu
  0 siblings, 0 replies; 12+ messages in thread
From: Barret Rhoden @ 2020-01-07 19:16 UTC (permalink / raw)
  To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	David Woodhouse, Joerg Roedel, Yian Chen, Sohil Mehta
  Cc: linux-kernel, iommu, x86

Commit f036c7fa0ab6 ("iommu/vt-d: Check VT-d RMRR region in BIOS is
reported as reserved") caused a machine to fail to boot for me, but only
after a kexec.

Buggy firmware provided an RMRR entry with base and end both == 0.  That
is an invalid RMRR format, and only happens to pass the RMRR sanity
check.  After a kexec, that entry fails the RMRR sanity check, due to a
slight change in the first e820 mapping.  See the v1 link for details.

v1->v2:
v1: https://lore.kernel.org/lkml/20191211194606.87940-1-brho@google.com/
- Added the TAINT_FIRMWARE_WORKAROUND
- Dropped the commit that treated missing e820 regions as "RMRR OK"


Barret Rhoden (2):
  iommu/vt-d: skip RMRR entries that fail the sanity check
  iommu/vt-d: skip invalid RMRR entries

 drivers/iommu/intel-iommu.c | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

-- 
2.24.1.735.g03f4e72817-goog


^ permalink raw reply	[flat|nested] 12+ messages in thread
* [PATCH v2 0/2] iommu/vt-d bad RMRR workarounds
@ 2020-01-07 19:16 ` Barret Rhoden via iommu
  0 siblings, 0 replies; 12+ messages in thread
From: Barret Rhoden via iommu @ 2020-01-07 19:16 UTC (permalink / raw)
  To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	David Woodhouse, Joerg Roedel, Yian Chen, Sohil Mehta
  Cc: iommu, x86, linux-kernel

Commit f036c7fa0ab6 ("iommu/vt-d: Check VT-d RMRR region in BIOS is
reported as reserved") caused a machine to fail to boot for me, but only
after a kexec.

Buggy firmware provided an RMRR entry with base and end both == 0.  That
is an invalid RMRR format, and only happens to pass the RMRR sanity
check.  After a kexec, that entry fails the RMRR sanity check, due to a
slight change in the first e820 mapping.  See the v1 link for details.

v1->v2:
v1: https://lore.kernel.org/lkml/20191211194606.87940-1-brho@google.com/
- Added the TAINT_FIRMWARE_WORKAROUND
- Dropped the commit that treated missing e820 regions as "RMRR OK"


Barret Rhoden (2):
  iommu/vt-d: skip RMRR entries that fail the sanity check
  iommu/vt-d: skip invalid RMRR entries

 drivers/iommu/intel-iommu.c | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

-- 
2.24.1.735.g03f4e72817-goog

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 12+ messages in thread
* [PATCH v2 1/2] iommu/vt-d: skip RMRR entries that fail the sanity check
  2020-01-07 19:16 ` Barret Rhoden via iommu
@ 2020-01-07 19:16   ` Barret Rhoden via iommu
  -1 siblings, 0 replies; 12+ messages in thread
From: Barret Rhoden @ 2020-01-07 19:16 UTC (permalink / raw)
  To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	David Woodhouse, Joerg Roedel, Yian Chen, Sohil Mehta
  Cc: linux-kernel, iommu, x86

RMRR entries describe memory regions that are DMA targets for devices
outside the kernel's control.

RMRR entries that fail the sanity check are pointing to regions of
memory that the firmware did not tell the kernel are reserved or
otherwise should not be used.

Instead of aborting DMAR processing, this commit skips these RMRR
entries and marks the firmware as tainted.  They will not be mapped into
the IOMMU, but the IOMMU can still be utilized.  If anything, when the
IOMMU is on, those devices will not be able to clobber RAM that the
kernel has allocated from those regions.

Signed-off-by: Barret Rhoden <brho@google.com>
---
 drivers/iommu/intel-iommu.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 0c8d81f56a30..a8bb458845bc 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4319,12 +4319,18 @@ int __init dmar_parse_one_rmrr(struct acpi_dmar_header *header, void *arg)
 {
 	struct acpi_dmar_reserved_memory *rmrr;
 	struct dmar_rmrr_unit *rmrru;
-	int ret;
 
 	rmrr = (struct acpi_dmar_reserved_memory *)header;
-	ret = arch_rmrr_sanity_check(rmrr);
-	if (ret)
-		return ret;
+	if (arch_rmrr_sanity_check(rmrr)) {
+		WARN_TAINT(1, TAINT_FIRMWARE_WORKAROUND,
+			   "Your BIOS is broken; bad RMRR [%#018Lx-%#018Lx]\n"
+			   "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
+			   rmrr->base_address, rmrr->end_address,
+			   dmi_get_system_info(DMI_BIOS_VENDOR),
+			   dmi_get_system_info(DMI_BIOS_VERSION),
+			   dmi_get_system_info(DMI_PRODUCT_VERSION));
+		return 0;
+	}
 
 	rmrru = kzalloc(sizeof(*rmrru), GFP_KERNEL);
 	if (!rmrru)
-- 
2.24.1.735.g03f4e72817-goog


^ permalink raw reply related	[flat|nested] 12+ messages in thread
* [PATCH v2 1/2] iommu/vt-d: skip RMRR entries that fail the sanity check
@ 2020-01-07 19:16   ` Barret Rhoden via iommu
  0 siblings, 0 replies; 12+ messages in thread
From: Barret Rhoden via iommu @ 2020-01-07 19:16 UTC (permalink / raw)
  To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	David Woodhouse, Joerg Roedel, Yian Chen, Sohil Mehta
  Cc: iommu, x86, linux-kernel

RMRR entries describe memory regions that are DMA targets for devices
outside the kernel's control.

RMRR entries that fail the sanity check are pointing to regions of
memory that the firmware did not tell the kernel are reserved or
otherwise should not be used.

Instead of aborting DMAR processing, this commit skips these RMRR
entries and marks the firmware as tainted.  They will not be mapped into
the IOMMU, but the IOMMU can still be utilized.  If anything, when the
IOMMU is on, those devices will not be able to clobber RAM that the
kernel has allocated from those regions.

Signed-off-by: Barret Rhoden <brho@google.com>
---
 drivers/iommu/intel-iommu.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 0c8d81f56a30..a8bb458845bc 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4319,12 +4319,18 @@ int __init dmar_parse_one_rmrr(struct acpi_dmar_header *header, void *arg)
 {
 	struct acpi_dmar_reserved_memory *rmrr;
 	struct dmar_rmrr_unit *rmrru;
-	int ret;
 
 	rmrr = (struct acpi_dmar_reserved_memory *)header;
-	ret = arch_rmrr_sanity_check(rmrr);
-	if (ret)
-		return ret;
+	if (arch_rmrr_sanity_check(rmrr)) {
+		WARN_TAINT(1, TAINT_FIRMWARE_WORKAROUND,
+			   "Your BIOS is broken; bad RMRR [%#018Lx-%#018Lx]\n"
+			   "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
+			   rmrr->base_address, rmrr->end_address,
+			   dmi_get_system_info(DMI_BIOS_VENDOR),
+			   dmi_get_system_info(DMI_BIOS_VERSION),
+			   dmi_get_system_info(DMI_PRODUCT_VERSION));
+		return 0;
+	}
 
 	rmrru = kzalloc(sizeof(*rmrru), GFP_KERNEL);
 	if (!rmrru)
-- 
2.24.1.735.g03f4e72817-goog

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply related	[flat|nested] 12+ messages in thread
* [PATCH v2 2/2] iommu/vt-d: skip invalid RMRR entries
  2020-01-07 19:16 ` Barret Rhoden via iommu
@ 2020-01-07 19:16   ` Barret Rhoden via iommu
  -1 siblings, 0 replies; 12+ messages in thread
From: Barret Rhoden @ 2020-01-07 19:16 UTC (permalink / raw)
  To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	David Woodhouse, Joerg Roedel, Yian Chen, Sohil Mehta
  Cc: linux-kernel, iommu, x86

The VT-d docs specify requirements for the RMRR entries base and end
(called 'Limit' in the docs) addresses.

This commit will cause the DMAR processing to skip any RMRR entries that
do not meet these requirements and mark the firmware as tainted, since
the firmware is giving us junk.

Signed-off-by: Barret Rhoden <brho@google.com>
---
 drivers/iommu/intel-iommu.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index a8bb458845bc..32c3c6338a3d 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4315,13 +4315,25 @@ static void __init init_iommu_pm_ops(void)
 static inline void init_iommu_pm_ops(void) {}
 #endif	/* CONFIG_PM */
 
+static int rmrr_validity_check(struct acpi_dmar_reserved_memory *rmrr)
+{
+	if ((rmrr->base_address & PAGE_MASK) ||
+	    (rmrr->end_address <= rmrr->base_address) ||
+	    ((rmrr->end_address - rmrr->base_address + 1) & PAGE_MASK)) {
+		pr_err(FW_BUG "Broken RMRR base: %#018Lx end: %#018Lx\n",
+		       rmrr->base_address, rmrr->end_address);
+		return -EINVAL;
+	}
+	return 0;
+}
+
 int __init dmar_parse_one_rmrr(struct acpi_dmar_header *header, void *arg)
 {
 	struct acpi_dmar_reserved_memory *rmrr;
 	struct dmar_rmrr_unit *rmrru;
 
 	rmrr = (struct acpi_dmar_reserved_memory *)header;
-	if (arch_rmrr_sanity_check(rmrr)) {
+	if (rmrr_validity_check(rmrr) || arch_rmrr_sanity_check(rmrr)) {
 		WARN_TAINT(1, TAINT_FIRMWARE_WORKAROUND,
 			   "Your BIOS is broken; bad RMRR [%#018Lx-%#018Lx]\n"
 			   "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
-- 
2.24.1.735.g03f4e72817-goog


^ permalink raw reply related	[flat|nested] 12+ messages in thread
* [PATCH v2 2/2] iommu/vt-d: skip invalid RMRR entries
@ 2020-01-07 19:16   ` Barret Rhoden via iommu
  0 siblings, 0 replies; 12+ messages in thread
From: Barret Rhoden via iommu @ 2020-01-07 19:16 UTC (permalink / raw)
  To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	David Woodhouse, Joerg Roedel, Yian Chen, Sohil Mehta
  Cc: iommu, x86, linux-kernel

The VT-d docs specify requirements for the RMRR entries base and end
(called 'Limit' in the docs) addresses.

This commit will cause the DMAR processing to skip any RMRR entries that
do not meet these requirements and mark the firmware as tainted, since
the firmware is giving us junk.

Signed-off-by: Barret Rhoden <brho@google.com>
---
 drivers/iommu/intel-iommu.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index a8bb458845bc..32c3c6338a3d 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4315,13 +4315,25 @@ static void __init init_iommu_pm_ops(void)
 static inline void init_iommu_pm_ops(void) {}
 #endif	/* CONFIG_PM */
 
+static int rmrr_validity_check(struct acpi_dmar_reserved_memory *rmrr)
+{
+	if ((rmrr->base_address & PAGE_MASK) ||
+	    (rmrr->end_address <= rmrr->base_address) ||
+	    ((rmrr->end_address - rmrr->base_address + 1) & PAGE_MASK)) {
+		pr_err(FW_BUG "Broken RMRR base: %#018Lx end: %#018Lx\n",
+		       rmrr->base_address, rmrr->end_address);
+		return -EINVAL;
+	}
+	return 0;
+}
+
 int __init dmar_parse_one_rmrr(struct acpi_dmar_header *header, void *arg)
 {
 	struct acpi_dmar_reserved_memory *rmrr;
 	struct dmar_rmrr_unit *rmrru;
 
 	rmrr = (struct acpi_dmar_reserved_memory *)header;
-	if (arch_rmrr_sanity_check(rmrr)) {
+	if (rmrr_validity_check(rmrr) || arch_rmrr_sanity_check(rmrr)) {
 		WARN_TAINT(1, TAINT_FIRMWARE_WORKAROUND,
 			   "Your BIOS is broken; bad RMRR [%#018Lx-%#018Lx]\n"
 			   "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
-- 
2.24.1.735.g03f4e72817-goog

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply related	[flat|nested] 12+ messages in thread
* Re: [PATCH v2 2/2] iommu/vt-d: skip invalid RMRR entries
  2020-01-07 19:16   ` Barret Rhoden via iommu
@ 2020-01-08  1:27     ` Lu Baolu
  -1 siblings, 0 replies; 12+ messages in thread
From: Lu Baolu @ 2020-01-08  1:27 UTC (permalink / raw)
  To: Barret Rhoden, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
	H. Peter Anvin, David Woodhouse, Joerg Roedel, Yian Chen,
	Sohil Mehta
  Cc: baolu.lu, iommu, x86, linux-kernel

Hi,

On 1/8/20 3:16 AM, Barret Rhoden via iommu wrote:
> The VT-d docs specify requirements for the RMRR entries base and end
> (called 'Limit' in the docs) addresses.
> 
> This commit will cause the DMAR processing to skip any RMRR entries that
> do not meet these requirements and mark the firmware as tainted, since
> the firmware is giving us junk.
> 
> Signed-off-by: Barret Rhoden <brho@google.com>
> ---
>   drivers/iommu/intel-iommu.c | 14 +++++++++++++-
>   1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index a8bb458845bc..32c3c6338a3d 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -4315,13 +4315,25 @@ static void __init init_iommu_pm_ops(void)
>   static inline void init_iommu_pm_ops(void) {}
>   #endif	/* CONFIG_PM */
>   
> +static int rmrr_validity_check(struct acpi_dmar_reserved_memory *rmrr)
> +{
> +	if ((rmrr->base_address & PAGE_MASK) ||
> +	    (rmrr->end_address <= rmrr->base_address) ||
> +	    ((rmrr->end_address - rmrr->base_address + 1) & PAGE_MASK)) {
> +		pr_err(FW_BUG "Broken RMRR base: %#018Lx end: %#018Lx\n",
> +		       rmrr->base_address, rmrr->end_address);

Since you will WARN_TAINT below, do you still want an error message
here?

> +		return -EINVAL;
> +	}
> +	return 0;
> +}
> +
>   int __init dmar_parse_one_rmrr(struct acpi_dmar_header *header, void *arg)
>   {
>   	struct acpi_dmar_reserved_memory *rmrr;
>   	struct dmar_rmrr_unit *rmrru;
>   
>   	rmrr = (struct acpi_dmar_reserved_memory *)header;
> -	if (arch_rmrr_sanity_check(rmrr)) {
> +	if (rmrr_validity_check(rmrr) || arch_rmrr_sanity_check(rmrr)) {
>   		WARN_TAINT(1, TAINT_FIRMWARE_WORKAROUND,
>   			   "Your BIOS is broken; bad RMRR [%#018Lx-%#018Lx]\n"
>   			   "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
> 

Best regards,
baolu

^ permalink raw reply	[flat|nested] 12+ messages in thread
* Re: [PATCH v2 2/2] iommu/vt-d: skip invalid RMRR entries
@ 2020-01-08  1:27     ` Lu Baolu
  0 siblings, 0 replies; 12+ messages in thread
From: Lu Baolu @ 2020-01-08  1:27 UTC (permalink / raw)
  To: Barret Rhoden, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
	H. Peter Anvin, David Woodhouse, Joerg Roedel, Yian Chen,
	Sohil Mehta
  Cc: iommu, x86, linux-kernel

Hi,

On 1/8/20 3:16 AM, Barret Rhoden via iommu wrote:
> The VT-d docs specify requirements for the RMRR entries base and end
> (called 'Limit' in the docs) addresses.
> 
> This commit will cause the DMAR processing to skip any RMRR entries that
> do not meet these requirements and mark the firmware as tainted, since
> the firmware is giving us junk.
> 
> Signed-off-by: Barret Rhoden <brho@google.com>
> ---
>   drivers/iommu/intel-iommu.c | 14 +++++++++++++-
>   1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index a8bb458845bc..32c3c6338a3d 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -4315,13 +4315,25 @@ static void __init init_iommu_pm_ops(void)
>   static inline void init_iommu_pm_ops(void) {}
>   #endif	/* CONFIG_PM */
>   
> +static int rmrr_validity_check(struct acpi_dmar_reserved_memory *rmrr)
> +{
> +	if ((rmrr->base_address & PAGE_MASK) ||
> +	    (rmrr->end_address <= rmrr->base_address) ||
> +	    ((rmrr->end_address - rmrr->base_address + 1) & PAGE_MASK)) {
> +		pr_err(FW_BUG "Broken RMRR base: %#018Lx end: %#018Lx\n",
> +		       rmrr->base_address, rmrr->end_address);

Since you will WARN_TAINT below, do you still want an error message
here?

> +		return -EINVAL;
> +	}
> +	return 0;
> +}
> +
>   int __init dmar_parse_one_rmrr(struct acpi_dmar_header *header, void *arg)
>   {
>   	struct acpi_dmar_reserved_memory *rmrr;
>   	struct dmar_rmrr_unit *rmrru;
>   
>   	rmrr = (struct acpi_dmar_reserved_memory *)header;
> -	if (arch_rmrr_sanity_check(rmrr)) {
> +	if (rmrr_validity_check(rmrr) || arch_rmrr_sanity_check(rmrr)) {
>   		WARN_TAINT(1, TAINT_FIRMWARE_WORKAROUND,
>   			   "Your BIOS is broken; bad RMRR [%#018Lx-%#018Lx]\n"
>   			   "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
> 

Best regards,
baolu
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 12+ messages in thread
* Re: [PATCH v2 2/2] iommu/vt-d: skip invalid RMRR entries
  2020-01-08  1:27     ` Lu Baolu
@ 2020-01-08 17:35       ` Barret Rhoden via iommu
  -1 siblings, 0 replies; 12+ messages in thread
From: Barret Rhoden @ 2020-01-08 17:35 UTC (permalink / raw)
  To: Lu Baolu, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
	H. Peter Anvin, David Woodhouse, Joerg Roedel, Yian Chen,
	Sohil Mehta
  Cc: iommu, x86, linux-kernel

On 1/7/20 8:27 PM, Lu Baolu wrote:
>> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>> index a8bb458845bc..32c3c6338a3d 100644
>> --- a/drivers/iommu/intel-iommu.c
>> +++ b/drivers/iommu/intel-iommu.c
>> @@ -4315,13 +4315,25 @@ static void __init init_iommu_pm_ops(void)
>>   static inline void init_iommu_pm_ops(void) {}
>>   #endif    /* CONFIG_PM */
>> +static int rmrr_validity_check(struct acpi_dmar_reserved_memory *rmrr)
>> +{
>> +    if ((rmrr->base_address & PAGE_MASK) ||
>> +        (rmrr->end_address <= rmrr->base_address) ||
>> +        ((rmrr->end_address - rmrr->base_address + 1) & PAGE_MASK)) {
>> +        pr_err(FW_BUG "Broken RMRR base: %#018Lx end: %#018Lx\n",
>> +               rmrr->base_address, rmrr->end_address);
> 
> Since you will WARN_TAINT below, do you still want an error message
> here?

I'm fine either way.

I put it in since arch_rmrr_sanity_check() also has a pr_err():

	pr_err(FW_BUG "No firmware reserved region can cover this RMRR
                [%#018Lx-%#018Lx], contact BIOS vendor for fixes\n",
                start, end - 1);

Thanks,

Barret


^ permalink raw reply	[flat|nested] 12+ messages in thread
* Re: [PATCH v2 2/2] iommu/vt-d: skip invalid RMRR entries
@ 2020-01-08 17:35       ` Barret Rhoden via iommu
  0 siblings, 0 replies; 12+ messages in thread
From: Barret Rhoden via iommu @ 2020-01-08 17:35 UTC (permalink / raw)
  To: Lu Baolu, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
	H. Peter Anvin, David Woodhouse, Joerg Roedel, Yian Chen,
	Sohil Mehta
  Cc: iommu, x86, linux-kernel

On 1/7/20 8:27 PM, Lu Baolu wrote:
>> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>> index a8bb458845bc..32c3c6338a3d 100644
>> --- a/drivers/iommu/intel-iommu.c
>> +++ b/drivers/iommu/intel-iommu.c
>> @@ -4315,13 +4315,25 @@ static void __init init_iommu_pm_ops(void)
>>   static inline void init_iommu_pm_ops(void) {}
>>   #endif    /* CONFIG_PM */
>> +static int rmrr_validity_check(struct acpi_dmar_reserved_memory *rmrr)
>> +{
>> +    if ((rmrr->base_address & PAGE_MASK) ||
>> +        (rmrr->end_address <= rmrr->base_address) ||
>> +        ((rmrr->end_address - rmrr->base_address + 1) & PAGE_MASK)) {
>> +        pr_err(FW_BUG "Broken RMRR base: %#018Lx end: %#018Lx\n",
>> +               rmrr->base_address, rmrr->end_address);
> 
> Since you will WARN_TAINT below, do you still want an error message
> here?

I'm fine either way.

I put it in since arch_rmrr_sanity_check() also has a pr_err():

	pr_err(FW_BUG "No firmware reserved region can cover this RMRR
                [%#018Lx-%#018Lx], contact BIOS vendor for fixes\n",
                start, end - 1);

Thanks,

Barret

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 12+ messages in thread
* Re: [PATCH v2 2/2] iommu/vt-d: skip invalid RMRR entries
  2020-01-07 19:16   ` Barret Rhoden via iommu
@ 2020-01-10 19:27     ` Chen, Yian
  -1 siblings, 0 replies; 12+ messages in thread
From: Chen, Yian @ 2020-01-10 19:27 UTC (permalink / raw)
  To: Barret Rhoden, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
	H. Peter Anvin, David Woodhouse, Joerg Roedel, Sohil Mehta
  Cc: linux-kernel, iommu, x86

Hi Barret,

this looks good.

thanks
Yian

On 1/7/2020 11:16 AM, Barret Rhoden wrote:
> The VT-d docs specify requirements for the RMRR entries base and end
> (called 'Limit' in the docs) addresses.
>
> This commit will cause the DMAR processing to skip any RMRR entries that
> do not meet these requirements and mark the firmware as tainted, since
> the firmware is giving us junk.
>
> Signed-off-by: Barret Rhoden <brho@google.com>
> ---
>   drivers/iommu/intel-iommu.c | 14 +++++++++++++-
>   1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index a8bb458845bc..32c3c6338a3d 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -4315,13 +4315,25 @@ static void __init init_iommu_pm_ops(void)
>   static inline void init_iommu_pm_ops(void) {}
>   #endif	/* CONFIG_PM */
>   
> +static int rmrr_validity_check(struct acpi_dmar_reserved_memory *rmrr)
> +{
> +	if ((rmrr->base_address & PAGE_MASK) ||
> +	    (rmrr->end_address <= rmrr->base_address) ||
> +	    ((rmrr->end_address - rmrr->base_address + 1) & PAGE_MASK)) {
> +		pr_err(FW_BUG "Broken RMRR base: %#018Lx end: %#018Lx\n",
> +		       rmrr->base_address, rmrr->end_address);
> +		return -EINVAL;
> +	}
> +	return 0;
> +}
> +
>   int __init dmar_parse_one_rmrr(struct acpi_dmar_header *header, void *arg)
>   {
>   	struct acpi_dmar_reserved_memory *rmrr;
>   	struct dmar_rmrr_unit *rmrru;
>   
>   	rmrr = (struct acpi_dmar_reserved_memory *)header;
> -	if (arch_rmrr_sanity_check(rmrr)) {
> +	if (rmrr_validity_check(rmrr) || arch_rmrr_sanity_check(rmrr)) {
>   		WARN_TAINT(1, TAINT_FIRMWARE_WORKAROUND,
>   			   "Your BIOS is broken; bad RMRR [%#018Lx-%#018Lx]\n"
>   			   "BIOS vendor: %s; Ver: %s; Product Version: %s\n",


^ permalink raw reply	[flat|nested] 12+ messages in thread
* Re: [PATCH v2 2/2] iommu/vt-d: skip invalid RMRR entries
@ 2020-01-10 19:27     ` Chen, Yian
  0 siblings, 0 replies; 12+ messages in thread
From: Chen, Yian @ 2020-01-10 19:27 UTC (permalink / raw)
  To: Barret Rhoden, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
	H. Peter Anvin, David Woodhouse, Joerg Roedel, Sohil Mehta
  Cc: iommu, x86, linux-kernel

Hi Barret,

this looks good.

thanks
Yian

On 1/7/2020 11:16 AM, Barret Rhoden wrote:
> The VT-d docs specify requirements for the RMRR entries base and end
> (called 'Limit' in the docs) addresses.
>
> This commit will cause the DMAR processing to skip any RMRR entries that
> do not meet these requirements and mark the firmware as tainted, since
> the firmware is giving us junk.
>
> Signed-off-by: Barret Rhoden <brho@google.com>
> ---
>   drivers/iommu/intel-iommu.c | 14 +++++++++++++-
>   1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index a8bb458845bc..32c3c6338a3d 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -4315,13 +4315,25 @@ static void __init init_iommu_pm_ops(void)
>   static inline void init_iommu_pm_ops(void) {}
>   #endif	/* CONFIG_PM */
>   
> +static int rmrr_validity_check(struct acpi_dmar_reserved_memory *rmrr)
> +{
> +	if ((rmrr->base_address & PAGE_MASK) ||
> +	    (rmrr->end_address <= rmrr->base_address) ||
> +	    ((rmrr->end_address - rmrr->base_address + 1) & PAGE_MASK)) {
> +		pr_err(FW_BUG "Broken RMRR base: %#018Lx end: %#018Lx\n",
> +		       rmrr->base_address, rmrr->end_address);
> +		return -EINVAL;
> +	}
> +	return 0;
> +}
> +
>   int __init dmar_parse_one_rmrr(struct acpi_dmar_header *header, void *arg)
>   {
>   	struct acpi_dmar_reserved_memory *rmrr;
>   	struct dmar_rmrr_unit *rmrru;
>   
>   	rmrr = (struct acpi_dmar_reserved_memory *)header;
> -	if (arch_rmrr_sanity_check(rmrr)) {
> +	if (rmrr_validity_check(rmrr) || arch_rmrr_sanity_check(rmrr)) {
>   		WARN_TAINT(1, TAINT_FIRMWARE_WORKAROUND,
>   			   "Your BIOS is broken; bad RMRR [%#018Lx-%#018Lx]\n"
>   			   "BIOS vendor: %s; Ver: %s; Product Version: %s\n",

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^ permalink raw reply	[flat|nested] 12+ messages in thread
end of thread, other threads:[~2020-01-10 19:27 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-01-07 19:16 [PATCH v2 0/2] iommu/vt-d bad RMRR workarounds Barret Rhoden
2020-01-07 19:16 ` Barret Rhoden via iommu
2020-01-07 19:16 ` [PATCH v2 1/2] iommu/vt-d: skip RMRR entries that fail the sanity check Barret Rhoden
2020-01-07 19:16   ` Barret Rhoden via iommu
2020-01-07 19:16 ` [PATCH v2 2/2] iommu/vt-d: skip invalid RMRR entries Barret Rhoden
2020-01-07 19:16   ` Barret Rhoden via iommu
2020-01-08  1:27   ` Lu Baolu
2020-01-08  1:27     ` Lu Baolu
2020-01-08 17:35     ` Barret Rhoden
2020-01-08 17:35       ` Barret Rhoden via iommu
2020-01-10 19:27   ` Chen, Yian
2020-01-10 19:27     ` Chen, Yian

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