2020-11-10 07:22:01

by Zhenzhong Duan

[permalink] [raw]
Subject: [PATCH v2] iommu/vt-d: avoid unnecessory panic if iommu init fail in tboot system

"intel_iommu=off" command line is used to disable iommu but iommu is force
enabled in a tboot system for security reason.

However for better performance on high speed network device, a new option
"intel_iommu=tboot_noforce" is introduced to disable the force on.

By default kernel should panic if iommu init fail in tboot for security
reason, but it's unnecessory if we use "intel_iommu=tboot_noforce,off".

Fix the code setting force_on and move intel_iommu_tboot_noforce
from tboot code to intel iommu code.

Fixes: 7304e8f28bb2 ("iommu/vt-d: Correctly disable Intel IOMMU force on")
Signed-off-by: Zhenzhong Duan <[email protected]>
---
v2: move ckeck of intel_iommu_tboot_noforce into iommu code per Baolu.

arch/x86/kernel/tboot.c | 3 ---
drivers/iommu/intel/iommu.c | 5 +++--
include/linux/intel-iommu.h | 1 -
3 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
index 992fb14..420be87 100644
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -514,9 +514,6 @@ int tboot_force_iommu(void)
if (!tboot_enabled())
return 0;

- if (intel_iommu_tboot_noforce)
- return 1;
-
if (no_iommu || swiotlb || dmar_disabled)
pr_warn("Forcing Intel-IOMMU to enabled\n");

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 1b1ca63..4d9b298 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -179,7 +179,7 @@ static inline unsigned long virt_to_dma_pfn(void *p)
* (used when kernel is launched w/ TXT)
*/
static int force_on = 0;
-int intel_iommu_tboot_noforce;
+static int intel_iommu_tboot_noforce;
static int no_platform_optin;

#define ROOT_ENTRY_NR (VTD_PAGE_SIZE/sizeof(struct root_entry))
@@ -4885,7 +4885,8 @@ int __init intel_iommu_init(void)
* Intel IOMMU is required for a TXT/tboot launch or platform
* opt in, so enforce that.
*/
- force_on = tboot_force_iommu() || platform_optin_force_iommu();
+ force_on = (!intel_iommu_tboot_noforce && tboot_force_iommu()) ||
+ platform_optin_force_iommu();

if (iommu_init_mempool()) {
if (force_on)
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index fbf5b3e..d956987 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -798,7 +798,6 @@ struct context_entry *iommu_context_addr(struct intel_iommu *iommu, u8 bus,
extern int iommu_calculate_max_sagaw(struct intel_iommu *iommu);
extern int dmar_disabled;
extern int intel_iommu_enabled;
-extern int intel_iommu_tboot_noforce;
extern int intel_iommu_gfx_mapped;
#else
static inline int iommu_calculate_agaw(struct intel_iommu *iommu)
--
1.8.3.1


2020-11-10 15:56:26

by Lukasz Hawrylko

[permalink] [raw]
Subject: Re: [PATCH v2] iommu/vt-d: avoid unnecessory panic if iommu init fail in tboot system

Hi Zhenzhong

On Tue, 2020-11-10 at 15:19 +0800, Zhenzhong Duan wrote:
> "intel_iommu=off" command line is used to disable iommu but iommu is force
> enabled in a tboot system for security reason.
>
> However for better performance on high speed network device, a new option
> "intel_iommu=tboot_noforce" is introduced to disable the force on.
>
> By default kernel should panic if iommu init fail in tboot for security
> reason, but it's unnecessory if we use "intel_iommu=tboot_noforce,off".
>
> Fix the code setting force_on and move intel_iommu_tboot_noforce
> from tboot code to intel iommu code.
>
> Fixes: 7304e8f28bb2 ("iommu/vt-d: Correctly disable Intel IOMMU force on")
> Signed-off-by: Zhenzhong Duan <[email protected]>
> ---
> v2: move ckeck of intel_iommu_tboot_noforce into iommu code per Baolu.

I have check it on my TXT testing environment with latest TBOOT,
everything works as expected.

Thanks,
Lukasz

2020-11-11 00:28:23

by Zhenzhong Duan

[permalink] [raw]
Subject: Re: [PATCH v2] iommu/vt-d: avoid unnecessory panic if iommu init fail in tboot system

Hi Lukasz,

On Tue, Nov 10, 2020 at 11:53 PM Lukasz Hawrylko
<[email protected]> wrote:
>
> Hi Zhenzhong
>
> On Tue, 2020-11-10 at 15:19 +0800, Zhenzhong Duan wrote:
> > "intel_iommu=off" command line is used to disable iommu but iommu is force
> > enabled in a tboot system for security reason.
> >
> > However for better performance on high speed network device, a new option
> > "intel_iommu=tboot_noforce" is introduced to disable the force on.
> >
> > By default kernel should panic if iommu init fail in tboot for security
> > reason, but it's unnecessory if we use "intel_iommu=tboot_noforce,off".
> >
> > Fix the code setting force_on and move intel_iommu_tboot_noforce
> > from tboot code to intel iommu code.
> >
> > Fixes: 7304e8f28bb2 ("iommu/vt-d: Correctly disable Intel IOMMU force on")
> > Signed-off-by: Zhenzhong Duan <[email protected]>
> > ---
> > v2: move ckeck of intel_iommu_tboot_noforce into iommu code per Baolu.
>
> I have check it on my TXT testing environment with latest TBOOT,
> everything works as expected.

Thanks very much for help checking, may I have your Tested-by?

Zhenzhong

2020-11-11 02:27:17

by Baolu Lu

[permalink] [raw]
Subject: Re: [PATCH v2] iommu/vt-d: avoid unnecessory panic if iommu init fail in tboot system

Hi Zhenzhong,

On 11/10/20 3:19 PM, Zhenzhong Duan wrote:
> "intel_iommu=off" command line is used to disable iommu but iommu is force
> enabled in a tboot system for security reason.
>
> However for better performance on high speed network device, a new option
> "intel_iommu=tboot_noforce" is introduced to disable the force on.
>
> By default kernel should panic if iommu init fail in tboot for security
> reason, but it's unnecessory if we use "intel_iommu=tboot_noforce,off".
>
> Fix the code setting force_on and move intel_iommu_tboot_noforce
> from tboot code to intel iommu code.
>
> Fixes: 7304e8f28bb2 ("iommu/vt-d: Correctly disable Intel IOMMU force on")
> Signed-off-by: Zhenzhong Duan <[email protected]>

Thanks for the patch.

Acked-by: Lu Baolu <[email protected]>

Best regards,
baolu

> ---
> v2: move ckeck of intel_iommu_tboot_noforce into iommu code per Baolu.
>
> arch/x86/kernel/tboot.c | 3 ---
> drivers/iommu/intel/iommu.c | 5 +++--
> include/linux/intel-iommu.h | 1 -
> 3 files changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
> index 992fb14..420be87 100644
> --- a/arch/x86/kernel/tboot.c
> +++ b/arch/x86/kernel/tboot.c
> @@ -514,9 +514,6 @@ int tboot_force_iommu(void)
> if (!tboot_enabled())
> return 0;
>
> - if (intel_iommu_tboot_noforce)
> - return 1;
> -
> if (no_iommu || swiotlb || dmar_disabled)
> pr_warn("Forcing Intel-IOMMU to enabled\n");
>
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 1b1ca63..4d9b298 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -179,7 +179,7 @@ static inline unsigned long virt_to_dma_pfn(void *p)
> * (used when kernel is launched w/ TXT)
> */
> static int force_on = 0;
> -int intel_iommu_tboot_noforce;
> +static int intel_iommu_tboot_noforce;
> static int no_platform_optin;
>
> #define ROOT_ENTRY_NR (VTD_PAGE_SIZE/sizeof(struct root_entry))
> @@ -4885,7 +4885,8 @@ int __init intel_iommu_init(void)
> * Intel IOMMU is required for a TXT/tboot launch or platform
> * opt in, so enforce that.
> */
> - force_on = tboot_force_iommu() || platform_optin_force_iommu();
> + force_on = (!intel_iommu_tboot_noforce && tboot_force_iommu()) ||
> + platform_optin_force_iommu();
>
> if (iommu_init_mempool()) {
> if (force_on)
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index fbf5b3e..d956987 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -798,7 +798,6 @@ struct context_entry *iommu_context_addr(struct intel_iommu *iommu, u8 bus,
> extern int iommu_calculate_max_sagaw(struct intel_iommu *iommu);
> extern int dmar_disabled;
> extern int intel_iommu_enabled;
> -extern int intel_iommu_tboot_noforce;
> extern int intel_iommu_gfx_mapped;
> #else
> static inline int iommu_calculate_agaw(struct intel_iommu *iommu)
>

2020-11-12 08:15:37

by Lukasz Hawrylko

[permalink] [raw]
Subject: Re: [PATCH v2] iommu/vt-d: avoid unnecessory panic if iommu init fail in tboot system

On Tue, 2020-11-10 at 15:19 +0800, Zhenzhong Duan wrote:
> "intel_iommu=off" command line is used to disable iommu but iommu is force
> enabled in a tboot system for security reason.
>
> However for better performance on high speed network device, a new option
> "intel_iommu=tboot_noforce" is introduced to disable the force on.
>
> By default kernel should panic if iommu init fail in tboot for security
> reason, but it's unnecessory if we use "intel_iommu=tboot_noforce,off".
>
> Fix the code setting force_on and move intel_iommu_tboot_noforce
> from tboot code to intel iommu code.
>
> Fixes: 7304e8f28bb2 ("iommu/vt-d: Correctly disable Intel IOMMU force on")
> Signed-off-by: Zhenzhong Duan <[email protected]>
> ---
> v2: move ckeck of intel_iommu_tboot_noforce into iommu code per Baolu.
>

Tested-by: Lukasz Hawrylko <[email protected]>

2020-11-17 23:35:10

by Baolu Lu

[permalink] [raw]
Subject: Re: [PATCH v2] iommu/vt-d: avoid unnecessory panic if iommu init fail in tboot system

+Will

Please consider this patch for v5.10.

Best regards,
baolu

On 2020/11/10 15:19, Zhenzhong Duan wrote:
> "intel_iommu=off" command line is used to disable iommu but iommu is force
> enabled in a tboot system for security reason.
>
> However for better performance on high speed network device, a new option
> "intel_iommu=tboot_noforce" is introduced to disable the force on.
>
> By default kernel should panic if iommu init fail in tboot for security
> reason, but it's unnecessory if we use "intel_iommu=tboot_noforce,off".
>
> Fix the code setting force_on and move intel_iommu_tboot_noforce
> from tboot code to intel iommu code.
>
> Fixes: 7304e8f28bb2 ("iommu/vt-d: Correctly disable Intel IOMMU force on")
> Signed-off-by: Zhenzhong Duan <[email protected]>
> ---
> v2: move ckeck of intel_iommu_tboot_noforce into iommu code per Baolu.
>
> arch/x86/kernel/tboot.c | 3 ---
> drivers/iommu/intel/iommu.c | 5 +++--
> include/linux/intel-iommu.h | 1 -
> 3 files changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
> index 992fb14..420be87 100644
> --- a/arch/x86/kernel/tboot.c
> +++ b/arch/x86/kernel/tboot.c
> @@ -514,9 +514,6 @@ int tboot_force_iommu(void)
> if (!tboot_enabled())
> return 0;
>
> - if (intel_iommu_tboot_noforce)
> - return 1;
> -
> if (no_iommu || swiotlb || dmar_disabled)
> pr_warn("Forcing Intel-IOMMU to enabled\n");
>
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 1b1ca63..4d9b298 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -179,7 +179,7 @@ static inline unsigned long virt_to_dma_pfn(void *p)
> * (used when kernel is launched w/ TXT)
> */
> static int force_on = 0;
> -int intel_iommu_tboot_noforce;
> +static int intel_iommu_tboot_noforce;
> static int no_platform_optin;
>
> #define ROOT_ENTRY_NR (VTD_PAGE_SIZE/sizeof(struct root_entry))
> @@ -4885,7 +4885,8 @@ int __init intel_iommu_init(void)
> * Intel IOMMU is required for a TXT/tboot launch or platform
> * opt in, so enforce that.
> */
> - force_on = tboot_force_iommu() || platform_optin_force_iommu();
> + force_on = (!intel_iommu_tboot_noforce && tboot_force_iommu()) ||
> + platform_optin_force_iommu();
>
> if (iommu_init_mempool()) {
> if (force_on)
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index fbf5b3e..d956987 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -798,7 +798,6 @@ struct context_entry *iommu_context_addr(struct intel_iommu *iommu, u8 bus,
> extern int iommu_calculate_max_sagaw(struct intel_iommu *iommu);
> extern int dmar_disabled;
> extern int intel_iommu_enabled;
> -extern int intel_iommu_tboot_noforce;
> extern int intel_iommu_gfx_mapped;
> #else
> static inline int iommu_calculate_agaw(struct intel_iommu *iommu)
>

2020-11-18 13:33:21

by Will Deacon

[permalink] [raw]
Subject: Re: [PATCH v2] iommu/vt-d: avoid unnecessory panic if iommu init fail in tboot system

On Wed, Nov 18, 2020 at 07:32:25AM +0800, Lu Baolu wrote:
> Please consider this patch for v5.10.

Cheers, I'll stick this onto a fixes branch momentarily.

Will

2020-11-18 14:22:21

by Will Deacon

[permalink] [raw]
Subject: Re: [PATCH v2] iommu/vt-d: avoid unnecessory panic if iommu init fail in tboot system

On Tue, 10 Nov 2020 15:19:08 +0800, Zhenzhong Duan wrote:
> "intel_iommu=off" command line is used to disable iommu but iommu is force
> enabled in a tboot system for security reason.
>
> However for better performance on high speed network device, a new option
> "intel_iommu=tboot_noforce" is introduced to disable the force on.
>
> By default kernel should panic if iommu init fail in tboot for security
> reason, but it's unnecessory if we use "intel_iommu=tboot_noforce,off".
>
> [...]

Applied to arm64 (for-next/iommu/fixes), thanks!

[1/1] iommu/vt-d: Avoid panic if iommu init fails in tboot system
https://git.kernel.org/arm64/c/4d213e76a359

Cheers,
--
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev