linux-kernel - [PATCH v2 4/6] iommu/s390: support iova_to

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Message-ID: <20250124201826.348848-5-mjrosato@linux.ibm.com>
Date: Fri, 24 Jan 2025 15:18:24 -0500
From: Matthew Rosato <mjrosato@...ux.ibm.com>
To: joro@...tes.org, will@...nel.org, robin.murphy@....com,
        gerald.schaefer@...ux.ibm.com, schnelle@...ux.ibm.com
Cc: hca@...ux.ibm.com, gor@...ux.ibm.com, agordeev@...ux.ibm.com,
        svens@...ux.ibm.com, borntraeger@...ux.ibm.com, clegoate@...hat.com,
        iommu@...ts.linux.dev, linux-kernel@...r.kernel.org,
        linux-s390@...r.kernel.org
Subject: [PATCH v2 4/6] iommu/s390: support iova_to_phys for additional table regions

The origin_type of the dma_table is used to determine how many table
levels must be traversed for the translation.

Signed-off-by: Matthew Rosato <mjrosato@...ux.ibm.com>
---
 arch/s390/include/asm/pci_dma.h |  2 ++
 drivers/iommu/s390-iommu.c      | 52 ++++++++++++++++++++++++++++++++-
 2 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/arch/s390/include/asm/pci_dma.h b/arch/s390/include/asm/pci_dma.h
index 42d7cc4262ca..8d8962e4fd58 100644
--- a/arch/s390/include/asm/pci_dma.h
+++ b/arch/s390/include/asm/pci_dma.h
@@ -55,6 +55,8 @@ enum zpci_ioat_dtype {
 #define ZPCI_PT_BITS			8
 #define ZPCI_ST_SHIFT			(ZPCI_PT_BITS + PAGE_SHIFT)
 #define ZPCI_RT_SHIFT			(ZPCI_ST_SHIFT + ZPCI_TABLE_BITS)
+#define ZPCI_RS_SHIFT			(ZPCI_RT_SHIFT + ZPCI_TABLE_BITS)
+#define ZPCI_RF_SHIFT			(ZPCI_RS_SHIFT + ZPCI_TABLE_BITS)
 
 #define ZPCI_RTE_FLAG_MASK		0x3fffUL
 #define ZPCI_RTE_ADDR_MASK		(~ZPCI_RTE_FLAG_MASK)
diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index 73e0bb251bc1..88adc4efc53f 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -36,6 +36,16 @@ struct s390_domain {
 
 static struct iommu_domain blocking_domain;
 
+static inline unsigned int calc_rfx(dma_addr_t ptr)
+{
+	return ((unsigned long)ptr >> ZPCI_RF_SHIFT) & ZPCI_INDEX_MASK;
+}
+
+static inline unsigned int calc_rsx(dma_addr_t ptr)
+{
+	return ((unsigned long)ptr >> ZPCI_RS_SHIFT) & ZPCI_INDEX_MASK;
+}
+
 static inline unsigned int calc_rtx(dma_addr_t ptr)
 {
 	return ((unsigned long)ptr >> ZPCI_RT_SHIFT) & ZPCI_INDEX_MASK;
@@ -704,6 +714,43 @@ static int s390_iommu_map_pages(struct iommu_domain *domain,
 	return rc;
 }
 
+static unsigned long *get_rto_from_iova(struct s390_domain *domain,
+					dma_addr_t iova)
+{
+	unsigned long *rfo, *rso, *rto;
+	unsigned long rfe, rse;
+	unsigned int rfx, rsx;
+
+	switch (domain->origin_type) {
+	case ZPCI_TABLE_TYPE_RFX:
+		rfo = domain->dma_table;
+		goto itp_rf;
+	case ZPCI_TABLE_TYPE_RSX:
+		rso = domain->dma_table;
+		goto itp_rs;
+	case ZPCI_TABLE_TYPE_RTX:
+		return domain->dma_table;
+	default:
+		return NULL;
+	}
+
+itp_rf:
+	rfx = calc_rfx(iova);
+	rfe = READ_ONCE(rfo[rfx]);
+	if (!reg_entry_isvalid(rfe))
+		return NULL;
+	rso = get_rf_rso(rfe);
+
+itp_rs:
+	rsx = calc_rsx(iova);
+	rse = READ_ONCE(rso[rsx]);
+	if (!reg_entry_isvalid(rse))
+		return NULL;
+	rto = get_rs_rto(rse);
+
+	return rto;
+}
+
 static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
 					   dma_addr_t iova)
 {
@@ -717,10 +764,13 @@ static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
 	    iova > domain->geometry.aperture_end)
 		return 0;
 
+	rto = get_rto_from_iova(s390_domain, iova);
+	if (!rto)
+		return 0;
+
 	rtx = calc_rtx(iova);
 	sx = calc_sx(iova);
 	px = calc_px(iova);
-	rto = s390_domain->dma_table;
 
 	rte = READ_ONCE(rto[rtx]);
 	if (reg_entry_isvalid(rte)) {
-- 
2.48.1