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Groups > linux.kernel > #1580633 > unrolled thread

[PATCH] Revert: "PCI: Add ACS quirk for all Cavium devices"

Started byAlex Williamson <alex.williamson@redhat.com>
First post2017-02-14 17:20 +0100
Last post2017-02-15 18:00 +0100
Articles 3 — 1 participant

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  [PATCH] Revert: "PCI: Add ACS quirk for all Cavium devices" Alex Williamson <alex.williamson@redhat.com> - 2017-02-14 17:20 +0100
    Re: [PATCH] Revert: "PCI: Add ACS quirk for all Cavium devices" Alex Williamson <alex.williamson@redhat.com> - 2017-02-15 17:40 +0100
      Re: [PATCH] Revert: "PCI: Add ACS quirk for all Cavium devices" Alex Williamson <alex.williamson@redhat.com> - 2017-02-15 18:00 +0100

#1580633 — [PATCH] Revert: "PCI: Add ACS quirk for all Cavium devices"

FromAlex Williamson <alex.williamson@redhat.com>
Date2017-02-14 17:20 +0100
Subject[PATCH] Revert: "PCI: Add ACS quirk for all Cavium devices"
Message-ID<taNZD-44x-17@gated-at.bofh.it>
This reverts commit b404bcfbf035413dcce539c8ba2c9986d220d8ed.

The reverted commit makes no attempt to selectively consider devices,
current or future.  Instead, it whitelists the entire PCI vendor ID.
This is a reckless approach as we clearly cannot know whether future
device IDs within this vendor ID are susceptible to peer-to-peer.
Additionally, the comment suggests this quirk is only relevant to
ThunderX, which raises further doubt whether it is appropriate to
apply to the entire vendor ID.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Cc: Manish Jaggi <mjaggi@caviumnetworks.com>
Cc: Tirumalesh Chalamarla <tchalamarla@cavium.com>
---

Please submit a new quirk targeting specific devices

 drivers/pci/quirks.c |   15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 1800befa8b8b..449eabb438e2 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -4060,19 +4060,6 @@ static int pci_quirk_amd_sb_acs(struct pci_dev *dev, u16 acs_flags)
 #endif
 }
 
-static int pci_quirk_cavium_acs(struct pci_dev *dev, u16 acs_flags)
-{
-	/*
-	 * Cavium devices matching this quirk do not perform peer-to-peer
-	 * with other functions, allowing masking out these bits as if they
-	 * were unimplemented in the ACS capability.
-	 */
-	acs_flags &= ~(PCI_ACS_SV | PCI_ACS_TB | PCI_ACS_RR |
-		       PCI_ACS_CR | PCI_ACS_UF | PCI_ACS_DT);
-
-	return acs_flags ? 0 : 1;
-}
-
 /*
  * Many Intel PCH root ports do provide ACS-like features to disable peer
  * transactions and validate bus numbers in requests, but do not provide an
@@ -4276,8 +4263,6 @@ static int pci_quirk_mf_endpoint_acs(struct pci_dev *dev, u16 acs_flags)
 	{ PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_quirk_intel_spt_pch_acs },
 	{ 0x19a2, 0x710, pci_quirk_mf_endpoint_acs }, /* Emulex BE3-R */
 	{ 0x10df, 0x720, pci_quirk_mf_endpoint_acs }, /* Emulex Skyhawk-R */
-	/* Cavium ThunderX */
-	{ PCI_VENDOR_ID_CAVIUM, PCI_ANY_ID, pci_quirk_cavium_acs },
 	{ 0 }
 };
 

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#1581436

FromAlex Williamson <alex.williamson@redhat.com>
Date2017-02-15 17:40 +0100
Message-ID<tbaMy-2lv-13@gated-at.bofh.it>
In reply to#1580633
On Tue, 14 Feb 2017 09:18:18 -0700
Alex Williamson <alex.williamson@redhat.com> wrote:

> This reverts commit b404bcfbf035413dcce539c8ba2c9986d220d8ed.
> 
> The reverted commit makes no attempt to selectively consider devices,
> current or future.  Instead, it whitelists the entire PCI vendor ID.
> This is a reckless approach as we clearly cannot know whether future
> device IDs within this vendor ID are susceptible to peer-to-peer.
> Additionally, the comment suggests this quirk is only relevant to
> ThunderX, which raises further doubt whether it is appropriate to
> apply to the entire vendor ID.
> 
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> Cc: Manish Jaggi <mjaggi@caviumnetworks.com>
> Cc: Tirumalesh Chalamarla <tchalamarla@cavium.com>
> ---
> 
> Please submit a new quirk targeting specific devices

Sorry, I saw the date on the original commit as January 30, 2016 and
forgot we're now in 2017, so I figured that this had only recently gone
in.  Since it's actually been around since 4.6, I'll take a different
approach.  Instead of reverting, I'm going to assume that this applies
to ThunderX devices as per the comment.  I'll follow-up with a new
patch that only applies this to device IDs matching ThunderX as found
here http://pci-ids.ucw.cz/read/PC/177d  Perhaps in the meantime,
someone from Cavium will comment on which subset of those devices this
is actually relevant to.  Thanks,

Alex

> 
>  drivers/pci/quirks.c |   15 ---------------
>  1 file changed, 15 deletions(-)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 1800befa8b8b..449eabb438e2 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -4060,19 +4060,6 @@ static int pci_quirk_amd_sb_acs(struct pci_dev *dev, u16 acs_flags)
>  #endif
>  }
>  
> -static int pci_quirk_cavium_acs(struct pci_dev *dev, u16 acs_flags)
> -{
> -	/*
> -	 * Cavium devices matching this quirk do not perform peer-to-peer
> -	 * with other functions, allowing masking out these bits as if they
> -	 * were unimplemented in the ACS capability.
> -	 */
> -	acs_flags &= ~(PCI_ACS_SV | PCI_ACS_TB | PCI_ACS_RR |
> -		       PCI_ACS_CR | PCI_ACS_UF | PCI_ACS_DT);
> -
> -	return acs_flags ? 0 : 1;
> -}
> -
>  /*
>   * Many Intel PCH root ports do provide ACS-like features to disable peer
>   * transactions and validate bus numbers in requests, but do not provide an
> @@ -4276,8 +4263,6 @@ static int pci_quirk_mf_endpoint_acs(struct pci_dev *dev, u16 acs_flags)
>  	{ PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_quirk_intel_spt_pch_acs },
>  	{ 0x19a2, 0x710, pci_quirk_mf_endpoint_acs }, /* Emulex BE3-R */
>  	{ 0x10df, 0x720, pci_quirk_mf_endpoint_acs }, /* Emulex Skyhawk-R */
> -	/* Cavium ThunderX */
> -	{ PCI_VENDOR_ID_CAVIUM, PCI_ANY_ID, pci_quirk_cavium_acs },
>  	{ 0 }
>  };
>  
> 

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#1581454

FromAlex Williamson <alex.williamson@redhat.com>
Date2017-02-15 18:00 +0100
Message-ID<tbb5U-2sv-17@gated-at.bofh.it>
In reply to#1581436
On Wed, 15 Feb 2017 22:12:54 +0530
Manish Jaggi <mjaggi@caviumnetworks.com> wrote:

> Hi Alex,
> 
> On 2/15/2017 10:04 PM, Alex Williamson wrote:
> > On Tue, 14 Feb 2017 09:18:18 -0700
> > Alex Williamson <alex.williamson@redhat.com> wrote:
> >  
> >> This reverts commit b404bcfbf035413dcce539c8ba2c9986d220d8ed.
> >>
> >> The reverted commit makes no attempt to selectively consider devices,
> >> current or future.  Instead, it whitelists the entire PCI vendor ID.
> >> This is a reckless approach as we clearly cannot know whether future
> >> device IDs within this vendor ID are susceptible to peer-to-peer.
> >> Additionally, the comment suggests this quirk is only relevant to
> >> ThunderX, which raises further doubt whether it is appropriate to
> >> apply to the entire vendor ID.
> >>
> >> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> >> Cc: Manish Jaggi <mjaggi@caviumnetworks.com>
> >> Cc: Tirumalesh Chalamarla <tchalamarla@cavium.com>
> >> ---
> >>
> >> Please submit a new quirk targeting specific devices  
> > Sorry, I saw the date on the original commit as January 30, 2016 and
> > forgot we're now in 2017, so I figured that this had only recently gone
> > in.  Since it's actually been around since 4.6, I'll take a different
> > approach.  Instead of reverting, I'm going to assume that this applies
> > to ThunderX devices as per the comment.  I'll follow-up with a new
> > patch that only applies this to device IDs matching ThunderX as found
> > here http://pci-ids.ucw.cz/read/PC/177d  Perhaps in the meantime,
> > someone from Cavium will comment on which subset of those devices this
> > is actually relevant to.  
> I will provide another patch with the specific device Ids.

Perfect, thank you Manish.

Alex

> >>   drivers/pci/quirks.c |   15 ---------------
> >>   1 file changed, 15 deletions(-)
> >>
> >> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> >> index 1800befa8b8b..449eabb438e2 100644
> >> --- a/drivers/pci/quirks.c
> >> +++ b/drivers/pci/quirks.c
> >> @@ -4060,19 +4060,6 @@ static int pci_quirk_amd_sb_acs(struct pci_dev *dev, u16 acs_flags)
> >>   #endif
> >>   }
> >>   
> >> -static int pci_quirk_cavium_acs(struct pci_dev *dev, u16 acs_flags)
> >> -{
> >> -	/*
> >> -	 * Cavium devices matching this quirk do not perform peer-to-peer
> >> -	 * with other functions, allowing masking out these bits as if they
> >> -	 * were unimplemented in the ACS capability.
> >> -	 */
> >> -	acs_flags &= ~(PCI_ACS_SV | PCI_ACS_TB | PCI_ACS_RR |
> >> -		       PCI_ACS_CR | PCI_ACS_UF | PCI_ACS_DT);
> >> -
> >> -	return acs_flags ? 0 : 1;
> >> -}
> >> -
> >>   /*
> >>    * Many Intel PCH root ports do provide ACS-like features to disable peer
> >>    * transactions and validate bus numbers in requests, but do not provide an
> >> @@ -4276,8 +4263,6 @@ static int pci_quirk_mf_endpoint_acs(struct pci_dev *dev, u16 acs_flags)
> >>   	{ PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_quirk_intel_spt_pch_acs },
> >>   	{ 0x19a2, 0x710, pci_quirk_mf_endpoint_acs }, /* Emulex BE3-R */
> >>   	{ 0x10df, 0x720, pci_quirk_mf_endpoint_acs }, /* Emulex Skyhawk-R */
> >> -	/* Cavium ThunderX */
> >> -	{ PCI_VENDOR_ID_CAVIUM, PCI_ANY_ID, pci_quirk_cavium_acs },
> >>   	{ 0 }
> >>   };
> >>   
> >>  
> 

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