RE: [PATCH 2/3 v2] iommu/fsl: Enable default DMA window for PCIe devices
From: Bhushan Bharat-R65777 <hidden>
Date: 2013-10-16 16:50:11
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linux-iommu, lkml
-----Original Message----- From: Sethi Varun-B16395 Sent: Wednesday, October 16, 2013 4:53 PM To: joro@8bytes.org; iommu@lists.linux-foundation.org; linuxppc- dev@lists.ozlabs.org; linux-kernel@vger.kernel.org; Yoder Stuart-B08248; =
Wood
Scott-B07421; alex.williamson@redhat.com; Bhushan Bharat-R65777 Cc: Sethi Varun-B16395 Subject: [PATCH 2/3 v2] iommu/fsl: Enable default DMA window for PCIe dev=
ices
=20 Once the PCIe device assigned to a guest VM (via VFIO) gets detached from=
the
iommu domain (when guest terminates), its PAMU table entry is disabled. S=
o, this
would prevent the device from being used once it's assigned back to the h=
ost.
=20 This patch allows for creation of a default DMA window corresponding to t=
he
device and subsequently enabling the PAMU table entry. Before we enable t=
he
entry, we ensure that the device's bus master capability is disabled (dev=
ice
quiesced). =20 Signed-off-by: Varun Sethi <redacted> --- drivers/iommu/fsl_pamu.c | 43 ++++++++++++++++++++++++++++-----=
---
drivers/iommu/fsl_pamu.h | 1 + drivers/iommu/fsl_pamu_domain.c | 46 +++++++++++++++++++++++++++++++++=
+++---
quoted hunk ↗ jump to hunk
3 files changed, 78 insertions(+), 12 deletions(-) =20diff --git a/drivers/iommu/fsl_pamu.c b/drivers/iommu/fsl_pamu.c indexcba0498..fb4a031 100644--- a/drivers/iommu/fsl_pamu.c +++ b/drivers/iommu/fsl_pamu.c@@ -225,6 +225,21 @@ static struct paace *pamu_get_spaace(struct paace *p=
aace,
u32 wnum)
return spaace;
}
=20
+/*
+ * Defaul PPAACE settings for an LIODN.
+ */
+static void setup_default_ppaace(struct paace *ppaace) {
+ pamu_init_ppaace(ppaace);
+ /* window size is 2^(WSE+1) bytes */
+ set_bf(ppaace->addr_bitfields, PPAACE_AF_WSE, 35);
+ ppaace->wbah =3D 0;
+ set_bf(ppaace->addr_bitfields, PPAACE_AF_WBAL, 0);
+ set_bf(ppaace->impl_attr, PAACE_IA_ATM,
+ PAACE_ATM_NO_XLATE);
+ set_bf(ppaace->addr_bitfields, PAACE_AF_AP,
+ PAACE_AP_PERMS_ALL);
+}
/**
* pamu_get_fspi_and_allocate() - Allocates fspi index and reserves subw=indows
* required for primary PAACE in the seco=
ndary
quoted hunk ↗ jump to hunk
@@ -253,6 +268,24 @@ static unsigned long pamu_get_fspi_and_allocate(u32subwin_cnt) return (spaace_addr - (unsigned long)spaact) / (sizeof(struct paace)); =
}
=20
+/* Reset the PAACE entry to the default state */ void
+enable_default_dma_window(int liodn) {
+ struct paace *ppaace;
+
+ ppaace =3D pamu_get_ppaace(liodn);
+ if (!ppaace) {
+ pr_debug("Invalid liodn entry\n");
+ return;
+ }
+
+ memset(ppaace, 0, sizeof(struct paace));
+
+ setup_default_ppaace(ppaace);
+ mb();
+ pamu_enable_liodn(liodn);
+}
+
/* Release the subwindows reserved for a particular LIODN */ void
pamu_free_subwins(int liodn) { @@ -752,15 +785,7 @@ static void __init
setup_liodns(void)
continue;
}
ppaace =3D pamu_get_ppaace(liodn);
- pamu_init_ppaace(ppaace);
- /* window size is 2^(WSE+1) bytes */
- set_bf(ppaace->addr_bitfields, PPAACE_AF_WSE, 35);
- ppaace->wbah =3D 0;
- set_bf(ppaace->addr_bitfields, PPAACE_AF_WBAL, 0);
- set_bf(ppaace->impl_attr, PAACE_IA_ATM,
- PAACE_ATM_NO_XLATE);
- set_bf(ppaace->addr_bitfields, PAACE_AF_AP,
- PAACE_AP_PERMS_ALL);
+ setup_default_ppaace(ppaace);
if (of_device_is_compatible(node, "fsl,qman-portal"))
setup_qbman_paace(ppaace, QMAN_PORTAL_PAACE);
if (of_device_is_compatible(node, "fsl,qman")) diff --git
a/drivers/iommu/fsl_pamu.h b/drivers/iommu/fsl_pamu.h index 8fc1a12..0edc=bbbb
quoted hunk ↗ jump to hunk
100644--- a/drivers/iommu/fsl_pamu.h +++ b/drivers/iommu/fsl_pamu.h@@ -406,5 +406,6 @@ void get_ome_index(u32 *omi_index, struct device *dev=
); int
quoted hunk ↗ jump to hunk
pamu_update_paace_stash(int liodn, u32 subwin, u32 value); int pamu_disable_spaace(int liodn, u32 subwin); u32 pamu_get_max_subwin_cnt(void); +void enable_default_dma_window(int liodn); =20 #endif /* __FSL_PAMU_H */diff --git a/drivers/iommu/fsl_pamu_domain.c b/drivers/iommu/fsl_pamu_dom=
ain.c
quoted hunk ↗ jump to hunk
index 966ae70..dd6cafc 100644--- a/drivers/iommu/fsl_pamu_domain.c +++ b/drivers/iommu/fsl_pamu_domain.c@@ -340,17 +340,57 @@ static inline struct device_domain_info*find_domain(struct device *dev) return dev->archdata.iommu_domain; } =20 +/* Disable device DMA capability and enable default DMA window */ +static void disable_device_dma(struct device_domain_info *info, + int enable_dma_window) +{ +#ifdef CONFIG_PCI + if (info->dev->bus =3D=3D &pci_bus_type) { + struct pci_dev *pdev =3D NULL; + pdev =3D to_pci_dev(info->dev); + if (pci_is_enabled(pdev)) + pci_disable_device(pdev); + } +#endif + + if (enable_dma_window) + enable_default_dma_window(info->liodn); +} + +static int check_for_shared_liodn(struct device_domain_info *info) { + struct device_domain_info *tmp; + + /* + * Sanity check, to ensure that this is not a + * shared LIODN. In case of a PCIe controller + * it's possible that all PCIe devices share + * the same LIODN. + */ + list_for_each_entry(tmp, &info->domain->devices, link) { + if (info->liodn =3D=3D tmp->liodn) + return 1; + } + + return 0; +} + static void remove_device_ref(struct device_domain_info *info, u32 win_c=
nt) { unsigned long flags;
+ int enable_dma_window =3D 0;
=20
list_del(&info->link);
spin_lock_irqsave(&iommu_lock, flags);
- if (win_cnt > 1)
- pamu_free_subwins(info->liodn);
- pamu_disable_liodn(info->liodn);
+ if (!check_for_shared_liodn(info)) {One query; Do we really need to check for this? Otherwise this patch series looks good to me. Thanks -Bharat
+ if (win_cnt > 1) + pamu_free_subwins(info->liodn); + pamu_disable_liodn(info->liodn); + enable_dma_window =3D 1; + } spin_unlock_irqrestore(&iommu_lock, flags); spin_lock_irqsave(&device_domain_lock, flags); + disable_device_dma(info, enable_dma_window); info->dev->archdata.iommu_domain =3D NULL; kmem_cache_free(iommu_devinfo_cache, info); spin_unlock_irqrestore(&device_domain_lock, flags); -- 1.7.9.5