Re: [PATCH v2 2/2] iommu/vt-d: Enable PASID only if device expects PASID in PRG Response.
On 2/13/19 12:26 AM, Tian, Kevin wrote: From: iommu-boun...@lists.linux-foundation.org [mailto:iommu- boun...@lists.linux-foundation.org] On Behalf Of sathyanarayanan.kuppusw...@linux.intel.com Sent: Tuesday, February 12, 2019 5:51 AM To: bhelg...@google.com; j...@8bytes.org; dw...@infradead.org Cc: Raj, Ashok ; linux-...@vger.kernel.org; linux- ker...@vger.kernel.org; Busch, Keith ; iommu@lists.linux-foundation.org; Pan, Jacob jun Subject: [PATCH v2 2/2] iommu/vt-d: Enable PASID only if device expects PASID in PRG Response. From: Kuppuswamy Sathyanarayanan In Intel IOMMU, if the Page Request Queue (PRQ) is full, it will automatically respond to the device with a success message as a keep alive. And when sending the success message, IOMMU will include PASID in the Response Message when the Page Request has a PASID in Request Message and It does not check against the PRG Response PASID requirement of the device before sending the response. Also, If the device receives the PRG response with PASID when its not expecting it then the device behavior is undefined. So enable PASID support only if device expects PASID in PRG response message. Cc: Ashok Raj Cc: Jacob Pan Cc: Keith Busch Suggested-by: Ashok Raj Signed-off-by: Kuppuswamy Sathyanarayanan --- drivers/iommu/intel-iommu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 1457f931218e..af2e4a011787 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -1399,7 +1399,8 @@ static void iommu_enable_dev_iotlb(struct device_domain_info *info) undefined. So always enable PASID support on devices which have it, even if we can't yet know if we're ever going to use it. */ - if (info->pasid_supported && !pci_enable_pasid(pdev, info- pasid_supported & ~1)) + if (info->pasid_supported && pci_prg_resp_pasid_required(pdev) && + !pci_enable_pasid(pdev, info->pasid_supported & ~1)) info->pasid_enabled = 1; Above logic looks problematic. As Dave commented in another thread, PRI and PASID are orthogonal capabilities. Especially with introduction of VT-d scalable mode, PASID will be used alone even w/o PRI... Why not doing the check when PRI is actually enabled? At that point you can fail the request if above condition is false. yes, makes sense. I will fix it in next version. if (info->pri_supported && !pci_reset_pri(pdev) && !pci_enable_pri(pdev, 32)) -- 2.20.1 ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu -- Sathyanarayanan Kuppuswamy Linux kernel developer ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [PATCH v2 2/2] iommu/vt-d: Enable PASID only if device expects PASID in PRG Response.
On Wed, Feb 13, 2019 at 12:26:33AM -0800, Tian, Kevin wrote: > > > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > > index 1457f931218e..af2e4a011787 100644 > > --- a/drivers/iommu/intel-iommu.c > > +++ b/drivers/iommu/intel-iommu.c > > @@ -1399,7 +1399,8 @@ static void iommu_enable_dev_iotlb(struct > > device_domain_info *info) > >undefined. So always enable PASID support on devices which > >have it, even if we can't yet know if we're ever going to > >use it. */ > > - if (info->pasid_supported && !pci_enable_pasid(pdev, info- > > >pasid_supported & ~1)) > > + if (info->pasid_supported && pci_prg_resp_pasid_required(pdev) > > && > > + !pci_enable_pasid(pdev, info->pasid_supported & ~1)) > > info->pasid_enabled = 1; > > Above logic looks problematic. As Dave commented in another thread, > PRI and PASID are orthogonal capabilities. Especially with introduction > of VT-d scalable mode, PASID will be used alone even w/o PRI... > > Why not doing the check when PRI is actually enabled? At that point > you can fail the request if above condition is false. > That makes sense. ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
RE: [PATCH v2 2/2] iommu/vt-d: Enable PASID only if device expects PASID in PRG Response.
> From: iommu-boun...@lists.linux-foundation.org [mailto:iommu- > boun...@lists.linux-foundation.org] On Behalf Of > sathyanarayanan.kuppusw...@linux.intel.com > Sent: Tuesday, February 12, 2019 5:51 AM > To: bhelg...@google.com; j...@8bytes.org; dw...@infradead.org > Cc: Raj, Ashok ; linux-...@vger.kernel.org; linux- > ker...@vger.kernel.org; Busch, Keith ; > iommu@lists.linux-foundation.org; Pan, Jacob jun > > Subject: [PATCH v2 2/2] iommu/vt-d: Enable PASID only if device expects > PASID in PRG Response. > > From: Kuppuswamy Sathyanarayanan > > > In Intel IOMMU, if the Page Request Queue (PRQ) is full, it will > automatically respond to the device with a success message as a keep > alive. And when sending the success message, IOMMU will include PASID in > the Response Message when the Page Request has a PASID in Request > Message and It does not check against the PRG Response PASID > requirement > of the device before sending the response. Also, If the device receives the > PRG response with PASID when its not expecting it then the device behavior > is undefined. So enable PASID support only if device expects PASID in PRG > response message. > > Cc: Ashok Raj > Cc: Jacob Pan > Cc: Keith Busch > Suggested-by: Ashok Raj > Signed-off-by: Kuppuswamy Sathyanarayanan > > --- > drivers/iommu/intel-iommu.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index 1457f931218e..af2e4a011787 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -1399,7 +1399,8 @@ static void iommu_enable_dev_iotlb(struct > device_domain_info *info) > undefined. So always enable PASID support on devices which > have it, even if we can't yet know if we're ever going to > use it. */ > - if (info->pasid_supported && !pci_enable_pasid(pdev, info- > >pasid_supported & ~1)) > + if (info->pasid_supported && pci_prg_resp_pasid_required(pdev) > && > + !pci_enable_pasid(pdev, info->pasid_supported & ~1)) > info->pasid_enabled = 1; Above logic looks problematic. As Dave commented in another thread, PRI and PASID are orthogonal capabilities. Especially with introduction of VT-d scalable mode, PASID will be used alone even w/o PRI... Why not doing the check when PRI is actually enabled? At that point you can fail the request if above condition is false. > > if (info->pri_supported && !pci_reset_pri(pdev) > && !pci_enable_pri(pdev, 32)) > -- > 2.20.1 > > ___ > iommu mailing list > iommu@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
[PATCH v2 2/2] iommu/vt-d: Enable PASID only if device expects PASID in PRG Response.
From: Kuppuswamy Sathyanarayanan In Intel IOMMU, if the Page Request Queue (PRQ) is full, it will automatically respond to the device with a success message as a keep alive. And when sending the success message, IOMMU will include PASID in the Response Message when the Page Request has a PASID in Request Message and It does not check against the PRG Response PASID requirement of the device before sending the response. Also, If the device receives the PRG response with PASID when its not expecting it then the device behavior is undefined. So enable PASID support only if device expects PASID in PRG response message. Cc: Ashok Raj Cc: Jacob Pan Cc: Keith Busch Suggested-by: Ashok Raj Signed-off-by: Kuppuswamy Sathyanarayanan --- drivers/iommu/intel-iommu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 1457f931218e..af2e4a011787 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -1399,7 +1399,8 @@ static void iommu_enable_dev_iotlb(struct device_domain_info *info) undefined. So always enable PASID support on devices which have it, even if we can't yet know if we're ever going to use it. */ - if (info->pasid_supported && !pci_enable_pasid(pdev, info->pasid_supported & ~1)) + if (info->pasid_supported && pci_prg_resp_pasid_required(pdev) && + !pci_enable_pasid(pdev, info->pasid_supported & ~1)) info->pasid_enabled = 1; if (info->pri_supported && !pci_reset_pri(pdev) && !pci_enable_pri(pdev, 32)) -- 2.20.1 ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
