linux-kernel - [RFC PATCH 5/7] iommu/amd: Add support for Guest IO protection

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Message-Id: <20210312090411.6030-6-suravee.suthikulpanit@amd.com>
Date:   Fri, 12 Mar 2021 03:04:09 -0600
From:   Suravee Suthikulpanit <suravee.suthikulpanit@....com>
To:     linux-kernel@...r.kernel.org, iommu@...ts.linux-foundation.org
Cc:     joro@...tes.org, Jon.Grimm@....com, Wei.Huang2@....com,
        Suravee Suthikulpanit <suravee.suthikulpanit@....com>
Subject: [RFC PATCH 5/7] iommu/amd: Add support for Guest IO protection

AMD IOMMU introduces support for Guest I/O protection where the request
from the I/O device without a PASID are treated as if they have PASID 0.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
---
 drivers/iommu/amd/amd_iommu_types.h | 3 +++
 drivers/iommu/amd/init.c            | 8 ++++++++
 drivers/iommu/amd/iommu.c           | 4 ++++
 3 files changed, 15 insertions(+)

diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index 25062eb86c8b..876ba1adf73e 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -93,6 +93,7 @@
 #define FEATURE_HE		(1ULL<<8)
 #define FEATURE_PC		(1ULL<<9)
 #define FEATURE_GAM_VAPIC	(1ULL<<21)
+#define FEATURE_GIOSUP		(1ULL<<48)
 #define FEATURE_EPHSUP		(1ULL<<50)
 #define FEATURE_SNP		(1ULL<<63)
 
@@ -366,6 +367,7 @@
 #define DTE_FLAG_IW (1ULL << 62)
 
 #define DTE_FLAG_IOTLB	(1ULL << 32)
+#define DTE_FLAG_GIOV	(1ULL << 54)
 #define DTE_FLAG_GV	(1ULL << 55)
 #define DTE_FLAG_MASK	(0x3ffULL << 32)
 #define DTE_GLX_SHIFT	(56)
@@ -519,6 +521,7 @@ struct protection_domain {
 	spinlock_t lock;	/* mostly used to lock the page table*/
 	u16 id;			/* the domain id written to the device table */
 	int glx;		/* Number of levels for GCR3 table */
+	bool giov;		/* guest IO protection domain */
 	u64 *gcr3_tbl;		/* Guest CR3 table */
 	unsigned long flags;	/* flags to find out type of domain */
 	unsigned dev_cnt;	/* devices assigned to this domain */
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 5def566de6f6..9265c1bf1d84 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -1895,6 +1895,12 @@ static int __init iommu_init_pci(struct amd_iommu *iommu)
 
 	init_iommu_perf_ctr(iommu);
 
+	if (amd_iommu_pgtable == AMD_IOMMU_V2 &&
+	    !iommu_feature(iommu, FEATURE_GIOSUP)) {
+		pr_warn("Cannot enable v2 page table for DMA-API. Fallback to v1.\n");
+		amd_iommu_pgtable = AMD_IOMMU_V1;
+	}
+
 	if (is_rd890_iommu(iommu->dev)) {
 		int i, j;
 
@@ -1969,6 +1975,8 @@ static void print_iommu_info(void)
 		if (amd_iommu_xt_mode == IRQ_REMAP_X2APIC_MODE)
 			pr_info("X2APIC enabled\n");
 	}
+	if (amd_iommu_pgtable == AMD_IOMMU_V2)
+		pr_info("GIOV enabled\n");
 }
 
 static int __init amd_iommu_init_pci(void)
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index f3800efdbb29..e29ece6e1e68 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -1405,6 +1405,10 @@ static void set_dte_entry(u16 devid, struct protection_domain *domain,
 
 	pte_root |= (domain->iop.mode & DEV_ENTRY_MODE_MASK)
 		    << DEV_ENTRY_MODE_SHIFT;
+
+	if (domain->giov && (domain->flags & PD_IOMMUV2_MASK))
+		pte_root |= DTE_FLAG_GIOV;
+
 	pte_root |= DTE_FLAG_IR | DTE_FLAG_IW | DTE_FLAG_V | DTE_FLAG_TV;
 
 	flags = amd_iommu_dev_table[devid].data[1];
-- 
2.17.1