+++ /dev/null
-From 43ff0796606a3f64adfeb24a92ec72935762cfe0 Mon Sep 17 00:00:00 2001
-From: Sasha Levin <sashal@kernel.org>
-Date: Wed, 26 Feb 2025 13:07:47 +0100
-Subject: s390/pci: Support mmap() of PCI resources except for ISM devices
-
-From: Niklas Schnelle <schnelle@linux.ibm.com>
-
-[ Upstream commit aa9f168d55dc47c0de564f7dfe0e90467c9fee71 ]
-
-So far s390 does not allow mmap() of PCI resources to user-space via the
-usual mechanisms, though it does use it for RDMA. For the PCI sysfs
-resource files and /proc/bus/pci it defines neither HAVE_PCI_MMAP nor
-ARCH_GENERIC_PCI_MMAP_RESOURCE. For vfio-pci s390 previously relied on
-disabled VFIO_PCI_MMAP and now relies on setting pdev->non_mappable_bars
-for all devices.
-
-This is partly because access to mapped PCI resources from user-space
-requires special PCI load/store memory-I/O (MIO) instructions, or the
-special MMIO syscalls when these are not available. Still, such access is
-possible and useful not just for RDMA, in fact not being able to mmap() PCI
-resources has previously caused extra work when testing devices.
-
-One thing that doesn't work with PCI resources mapped to user-space though
-is the s390 specific virtual ISM device. Not only because the BAR size of
-256 TiB prevents mapping the whole BAR but also because access requires use
-of the legacy PCI instructions which are not accessible to user-space on
-systems with the newer MIO PCI instructions.
-
-Now with the pdev->non_mappable_bars flag ISM can be excluded from mapping
-its resources while making this functionality available for all other PCI
-devices. To this end introduce a minimal implementation of PCI_QUIRKS and
-use that to set pdev->non_mappable_bars for ISM devices only. Then also set
-ARCH_GENERIC_PCI_MMAP_RESOURCE to take advantage of the generic
-implementation of pci_mmap_resource_range() enabling only the newer sysfs
-mmap() interface. This follows the recommendation in
-Documentation/PCI/sysfs-pci.rst.
-
-Link: https://lore.kernel.org/r/20250226-vfio_pci_mmap-v7-3-c5c0f1d26efd@linux.ibm.com
-Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
-Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
-Signed-off-by: Sasha Levin <sashal@kernel.org>
----
- arch/s390/Kconfig | 4 +---
- arch/s390/include/asm/pci.h | 3 +++
- arch/s390/pci/Makefile | 2 +-
- arch/s390/pci/pci_fixup.c | 23 +++++++++++++++++++++++
- drivers/s390/net/ism_drv.c | 1 -
- include/linux/pci_ids.h | 1 +
- 6 files changed, 29 insertions(+), 5 deletions(-)
- create mode 100644 arch/s390/pci/pci_fixup.c
-
-diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
-index 9c9ec08d78c71..e48741e001476 100644
---- a/arch/s390/Kconfig
-+++ b/arch/s390/Kconfig
-@@ -41,9 +41,6 @@ config AUDIT_ARCH
- config NO_IOPORT_MAP
- def_bool y
-
--config PCI_QUIRKS
-- def_bool n
--
- config ARCH_SUPPORTS_UPROBES
- def_bool y
-
-@@ -258,6 +255,7 @@ config S390
- select PCI_DOMAINS if PCI
- select PCI_MSI if PCI
- select PCI_MSI_ARCH_FALLBACKS if PCI_MSI
-+ select PCI_QUIRKS if PCI
- select SPARSE_IRQ
- select SWIOTLB
- select SYSCTL_EXCEPTION_TRACE
-diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
-index 474e1f8d1d3c2..d2086af3434c0 100644
---- a/arch/s390/include/asm/pci.h
-+++ b/arch/s390/include/asm/pci.h
-@@ -11,6 +11,9 @@
- #include <asm/pci_insn.h>
- #include <asm/sclp.h>
-
-+#define ARCH_GENERIC_PCI_MMAP_RESOURCE 1
-+#define arch_can_pci_mmap_wc() 1
-+
- #define PCIBIOS_MIN_IO 0x1000
- #define PCIBIOS_MIN_MEM 0x10000000
-
-diff --git a/arch/s390/pci/Makefile b/arch/s390/pci/Makefile
-index df73c5182990a..1810e0944a4ed 100644
---- a/arch/s390/pci/Makefile
-+++ b/arch/s390/pci/Makefile
-@@ -5,6 +5,6 @@
-
- obj-$(CONFIG_PCI) += pci.o pci_irq.o pci_clp.o \
- pci_event.o pci_debug.o pci_insn.o pci_mmio.o \
-- pci_bus.o pci_kvm_hook.o pci_report.o
-+ pci_bus.o pci_kvm_hook.o pci_report.o pci_fixup.o
- obj-$(CONFIG_PCI_IOV) += pci_iov.o
- obj-$(CONFIG_SYSFS) += pci_sysfs.o
-diff --git a/arch/s390/pci/pci_fixup.c b/arch/s390/pci/pci_fixup.c
-new file mode 100644
-index 0000000000000..35688b6450983
---- /dev/null
-+++ b/arch/s390/pci/pci_fixup.c
-@@ -0,0 +1,23 @@
-+// SPDX-License-Identifier: GPL-2.0
-+/*
-+ * Exceptions for specific devices,
-+ *
-+ * Copyright IBM Corp. 2025
-+ *
-+ * Author(s):
-+ * Niklas Schnelle <schnelle@linux.ibm.com>
-+ */
-+#include <linux/pci.h>
-+
-+static void zpci_ism_bar_no_mmap(struct pci_dev *pdev)
-+{
-+ /*
-+ * ISM's BAR is special. Drivers written for ISM know
-+ * how to handle this but others need to be aware of their
-+ * special nature e.g. to prevent attempts to mmap() it.
-+ */
-+ pdev->non_mappable_bars = 1;
-+}
-+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_IBM,
-+ PCI_DEVICE_ID_IBM_ISM,
-+ zpci_ism_bar_no_mmap);
-diff --git a/drivers/s390/net/ism_drv.c b/drivers/s390/net/ism_drv.c
-index 2f34761e64135..60ed70a39d2cc 100644
---- a/drivers/s390/net/ism_drv.c
-+++ b/drivers/s390/net/ism_drv.c
-@@ -20,7 +20,6 @@
- MODULE_DESCRIPTION("ISM driver for s390");
- MODULE_LICENSE("GPL");
-
--#define PCI_DEVICE_ID_IBM_ISM 0x04ED
- #define DRV_NAME "ism"
-
- static const struct pci_device_id ism_device_table[] = {
-diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
-index 2a9ca3dbaa0e9..5bd122a9afdc6 100644
---- a/include/linux/pci_ids.h
-+++ b/include/linux/pci_ids.h
-@@ -518,6 +518,7 @@
- #define PCI_DEVICE_ID_IBM_ICOM_V2_ONE_PORT_RVX_ONE_PORT_MDM 0x0251
- #define PCI_DEVICE_ID_IBM_ICOM_V2_ONE_PORT_RVX_ONE_PORT_MDM_PCIE 0x0361
- #define PCI_DEVICE_ID_IBM_ICOM_FOUR_PORT_MODEL 0x252
-+#define PCI_DEVICE_ID_IBM_ISM 0x04ed
-
- #define PCI_SUBVENDOR_ID_IBM 0x1014
- #define PCI_SUBDEVICE_ID_IBM_SATURN_SERIAL_ONE_PORT 0x03d4
---
-2.39.5
-
projects / thirdparty / kernel / stable-queue.git / commitdiff
