[PATCH] uio: uio_pci_generic: add memory resource mappings

From: Firas Ashkar <firas.ashkar@savoirfairelinux.com>
To: gregkh@linuxfoundation.org, mst@redhat.com
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Firas Ashkar <firas.ashkar@savoirfairelinux.com>
Subject: [PATCH] uio: uio_pci_generic: add memory resource mappings
Date: Tue, 27 Apr 2021 11:06:46 -0400	[thread overview]
Message-ID: <20210427150646.3074218-1-firas.ashkar@savoirfairelinux.com> (raw)

import memory resources from underlying pci device, thus allowing
userspace applications to memory map those resources.

Signed-off-by: Firas Ashkar <firas.ashkar@savoirfairelinux.com>
---
:100644 100644 c7d681fef198 efc43869131d M	drivers/uio/uio_pci_generic.c
 drivers/uio/uio_pci_generic.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/drivers/uio/uio_pci_generic.c b/drivers/uio/uio_pci_generic.c
index c7d681fef198..efc43869131d 100644
--- a/drivers/uio/uio_pci_generic.c
+++ b/drivers/uio/uio_pci_generic.c
@@ -72,7 +72,9 @@ static int probe(struct pci_dev *pdev,
 			   const struct pci_device_id *id)
 {
 	struct uio_pci_generic_dev *gdev;
+	struct uio_mem *uiomem;
 	int err;
+	int i;
 
 	err = pcim_enable_device(pdev);
 	if (err) {
@@ -101,6 +103,36 @@ static int probe(struct pci_dev *pdev,
 			 "no support for interrupts?\n");
 	}
 
+	uiomem = &gdev->info.mem[0];
+	for (i = 0; i < MAX_UIO_MAPS; ++i) {
+		struct resource *r = &pdev->resource[i];
+
+		if (r->flags != (IORESOURCE_SIZEALIGN | IORESOURCE_MEM))
+			continue;
+
+		if (uiomem >= &gdev->info.mem[MAX_UIO_MAPS]) {
+			dev_warn(
+				&pdev->dev,
+				"device has more than " __stringify(
+					MAX_UIO_MAPS) " I/O memory resources.\n");
+			break;
+		}
+
+		uiomem->memtype = UIO_MEM_PHYS;
+		uiomem->addr = r->start & PAGE_MASK;
+		uiomem->offs = r->start & ~PAGE_MASK;
+		uiomem->size =
+			(uiomem->offs + resource_size(r) + PAGE_SIZE - 1) &
+			PAGE_MASK;
+		uiomem->name = r->name;
+		++uiomem;
+	}
+
+	while (uiomem < &gdev->info.mem[MAX_UIO_MAPS]) {
+		uiomem->size = 0;
+		++uiomem;
+	}
+
 	return devm_uio_register_device(&pdev->dev, &gdev->info);
 }
 
-- 
2.25.1

