diff mbox series

[v5,5/8] iommu/arm-smmu-v3: Add bypass flag to arm_smmu_write_strtab_ent()

Message ID 20210524110222.2212-6-shameerali.kolothum.thodi@huawei.com (mailing list archive)
State Not Applicable, archived
Headers show
Series ACPI/IORT: Support for IORT RMR node | expand

Commit Message

Shameerali Kolothum Thodi May 24, 2021, 11:02 a.m. UTC
By default, disable_bypass is set and any dev without an iommu domain
installs STE with CFG_ABORT during arm_smmu_init_bypass_stes(). Introduce
a "bypass" flag to arm_smmu_write_strtab_ent() so that we can force it to
install CFG_BYPASS STE for specific SIDs. This will be useful in follow
up patch to install bypass for IORT RMR SIDs.

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

Robin Murphy June 14, 2021, 10:23 a.m. UTC | #1
On 2021-05-24 12:02, Shameer Kolothum wrote:
> By default, disable_bypass is set and any dev without an iommu domain
> installs STE with CFG_ABORT during arm_smmu_init_bypass_stes(). Introduce
> a "bypass" flag to arm_smmu_write_strtab_ent() so that we can force it to
> install CFG_BYPASS STE for specific SIDs. This will be useful in follow
> up patch to install bypass for IORT RMR SIDs.
> 
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> ---
>   drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index 754bad6092c1..f9195b740f48 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -1174,7 +1174,7 @@ static void arm_smmu_sync_ste_for_sid(struct arm_smmu_device *smmu, u32 sid)
>   }
>   
>   static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
> -				      __le64 *dst)
> +				      __le64 *dst, bool bypass)
>   {
>   	/*
>   	 * This is hideously complicated, but we only really care about
> @@ -1245,7 +1245,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
>   
>   	/* Bypass/fault */
>   	if (!smmu_domain || !(s1_cfg || s2_cfg)) {
> -		if (!smmu_domain && disable_bypass)
> +		if (!smmu_domain && disable_bypass && !bypass)

Umm...

>   			val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_ABORT);
>   		else
>   			val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_BYPASS);
> @@ -1320,7 +1320,7 @@ static void arm_smmu_init_bypass_stes(__le64 *strtab, unsigned int nent)
>   	unsigned int i;
>   
>   	for (i = 0; i < nent; ++i) {
> -		arm_smmu_write_strtab_ent(NULL, -1, strtab);
> +		arm_smmu_write_strtab_ent(NULL, -1, strtab, false);

...and in particular, an operation named "init_bypass_stes" passing 
bypass=false is just breaking my brain. Can we pull the logic for 
default bypass/fault out to here as part of the refactoring so that it 
actually makes sense?

Robin.

>   		strtab += STRTAB_STE_DWORDS;
>   	}
>   }
> @@ -2097,7 +2097,7 @@ static void arm_smmu_install_ste_for_dev(struct arm_smmu_master *master)
>   		if (j < i)
>   			continue;
>   
> -		arm_smmu_write_strtab_ent(master, sid, step);
> +		arm_smmu_write_strtab_ent(master, sid, step, false);
>   	}
>   }
>   
>
Shameerali Kolothum Thodi June 14, 2021, 12:51 p.m. UTC | #2
> -----Original Message-----
> From: Robin Murphy [mailto:robin.murphy@arm.com]
> Sent: 14 June 2021 11:23
> To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>;
> linux-arm-kernel@lists.infradead.org; linux-acpi@vger.kernel.org;
> iommu@lists.linux-foundation.org
> Cc: Linuxarm <linuxarm@huawei.com>; lorenzo.pieralisi@arm.com;
> joro@8bytes.org; wanghuiqiang <wanghuiqiang@huawei.com>; Guohanjun
> (Hanjun Guo) <guohanjun@huawei.com>; steven.price@arm.com;
> Sami.Mujawar@arm.com; jon@solid-run.com; eric.auger@redhat.com;
> yangyicong <yangyicong@huawei.com>
> Subject: Re: [PATCH v5 5/8] iommu/arm-smmu-v3: Add bypass flag
> to arm_smmu_write_strtab_ent()
> 
> On 2021-05-24 12:02, Shameer Kolothum wrote:
> > By default, disable_bypass is set and any dev without an iommu domain
> > installs STE with CFG_ABORT during arm_smmu_init_bypass_stes().
> Introduce
> > a "bypass" flag to arm_smmu_write_strtab_ent() so that we can force it to
> > install CFG_BYPASS STE for specific SIDs. This will be useful in follow
> > up patch to install bypass for IORT RMR SIDs.
> >
> > Signed-off-by: Shameer Kolothum
> <shameerali.kolothum.thodi@huawei.com>
> > ---
> >   drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 8 ++++----
> >   1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> > index 754bad6092c1..f9195b740f48 100644
> > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> > @@ -1174,7 +1174,7 @@ static void arm_smmu_sync_ste_for_sid(struct
> arm_smmu_device *smmu, u32 sid)
> >   }
> >
> >   static void arm_smmu_write_strtab_ent(struct arm_smmu_master
> *master, u32 sid,
> > -				      __le64 *dst)
> > +				      __le64 *dst, bool bypass)
> >   {
> >   	/*
> >   	 * This is hideously complicated, but we only really care about
> > @@ -1245,7 +1245,7 @@ static void arm_smmu_write_strtab_ent(struct
> arm_smmu_master *master, u32 sid,
> >
> >   	/* Bypass/fault */
> >   	if (!smmu_domain || !(s1_cfg || s2_cfg)) {
> > -		if (!smmu_domain && disable_bypass)
> > +		if (!smmu_domain && disable_bypass && !bypass)
> 
> Umm...
> 
> >   			val |= FIELD_PREP(STRTAB_STE_0_CFG,
> STRTAB_STE_0_CFG_ABORT);
> >   		else
> >   			val |= FIELD_PREP(STRTAB_STE_0_CFG,
> STRTAB_STE_0_CFG_BYPASS);
> > @@ -1320,7 +1320,7 @@ static void arm_smmu_init_bypass_stes(__le64
> *strtab, unsigned int nent)
> >   	unsigned int i;
> >
> >   	for (i = 0; i < nent; ++i) {
> > -		arm_smmu_write_strtab_ent(NULL, -1, strtab);
> > +		arm_smmu_write_strtab_ent(NULL, -1, strtab, false);
> 
> ...and in particular, an operation named "init_bypass_stes" passing
> bypass=false is just breaking my brain. Can we pull the logic for
> default bypass/fault out to here as part of the refactoring so that it
> actually makes sense?

Agree, it is confusing. Will add the default bypass/fault logic here.

Thanks,
Shameer

> 
> Robin.
> 
> >   		strtab += STRTAB_STE_DWORDS;
> >   	}
> >   }
> > @@ -2097,7 +2097,7 @@ static void arm_smmu_install_ste_for_dev(struct
> arm_smmu_master *master)
> >   		if (j < i)
> >   			continue;
> >
> > -		arm_smmu_write_strtab_ent(master, sid, step);
> > +		arm_smmu_write_strtab_ent(master, sid, step, false);
> >   	}
> >   }
> >
> >
diff mbox series

Patch

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 754bad6092c1..f9195b740f48 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1174,7 +1174,7 @@  static void arm_smmu_sync_ste_for_sid(struct arm_smmu_device *smmu, u32 sid)
 }
 
 static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
-				      __le64 *dst)
+				      __le64 *dst, bool bypass)
 {
 	/*
 	 * This is hideously complicated, but we only really care about
@@ -1245,7 +1245,7 @@  static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
 
 	/* Bypass/fault */
 	if (!smmu_domain || !(s1_cfg || s2_cfg)) {
-		if (!smmu_domain && disable_bypass)
+		if (!smmu_domain && disable_bypass && !bypass)
 			val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_ABORT);
 		else
 			val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_BYPASS);
@@ -1320,7 +1320,7 @@  static void arm_smmu_init_bypass_stes(__le64 *strtab, unsigned int nent)
 	unsigned int i;
 
 	for (i = 0; i < nent; ++i) {
-		arm_smmu_write_strtab_ent(NULL, -1, strtab);
+		arm_smmu_write_strtab_ent(NULL, -1, strtab, false);
 		strtab += STRTAB_STE_DWORDS;
 	}
 }
@@ -2097,7 +2097,7 @@  static void arm_smmu_install_ste_for_dev(struct arm_smmu_master *master)
 		if (j < i)
 			continue;
 
-		arm_smmu_write_strtab_ent(master, sid, step);
+		arm_smmu_write_strtab_ent(master, sid, step, false);
 	}
 }