PCI: Add pci_irq_type() to query the allocated interrupt typegrafted

Add a helper that returns PCI_IRQ_MSIX, PCI_IRQ_MSI, or PCI_IRQ_INTX
based on the interrupt type the PCI core selected after
pci_alloc_irq_vectors().

Several drivers already open-code this check against pdev->msix_enabled
and pdev->msi_enabled, or even open code this helper [1].

A common helper avoids the duplication and keeps drivers from accessing
the bitfield directly (see also [2]).

Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Link: https://elixir.bootlin.com/linux/v7.1/source/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c#L196 [1]
Inspired-by: John Hubbard <jhubbard@nvidia.com>
Link: https://lore.kernel.org/all/DKKG2QM3YJYB.Z2H2B2UXJ75N@kernel.org/ [2]
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260813165234.620555-5-dakr@kernel.org
[ Add missing pci_irq_type() stub for CONFIG_PCI=n. ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

1 files changed, 111 insertions, 0 deletions

diff --git a/drivers/firmware/efi/ovmf-debug-log.c b/drivers/firmware/efi/ovmf-debug-log.c
new file mode 100644
index 000000000..5b2471ffa
--- /dev/null
+++ b/drivers/firmware/efi/ovmf-debug-log.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/efi.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/kobject.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/sysfs.h>
+
+#define OVMF_DEBUG_LOG_MAGIC1  0x3167646d666d766f  // "ovmfmdg1"
+#define OVMF_DEBUG_LOG_MAGIC2  0x3267646d666d766f  // "ovmfmdg2"
+
+struct ovmf_debug_log_header {
+	u64    magic1;
+	u64    magic2;
+	u64    hdr_size;
+	u64    log_size;
+	u64    lock; // edk2 spinlock
+	u64    head_off;
+	u64    tail_off;
+	u64    truncated;
+	u8     fw_version[128];
+};
+
+static struct ovmf_debug_log_header *hdr;
+static u8 *logbuf;
+static u64 logbufsize;
+
+static ssize_t ovmf_log_read(struct file *filp, struct kobject *kobj,
+			     const struct bin_attribute *attr, char *buf,
+			     loff_t offset, size_t count)
+{
+	u64 start, end;
+
+	start = hdr->head_off + offset;
+	if (hdr->head_off > hdr->tail_off && start >= hdr->log_size)
+		start -= hdr->log_size;
+
+	end = start + count;
+	if (start > hdr->tail_off) {
+		if (end > hdr->log_size)
+			end = hdr->log_size;
+	} else {
+		if (end > hdr->tail_off)
+			end = hdr->tail_off;
+	}
+
+	if (start > logbufsize || end > logbufsize)
+		return 0;
+	if (start >= end)
+		return 0;
+
+	memcpy(buf, logbuf + start, end - start);
+	return end - start;
+}
+
+static struct bin_attribute ovmf_log_bin_attr = {
+	.attr = {
+		.name = "ovmf_debug_log",
+		.mode = 0444,
+	},
+	.read = ovmf_log_read,
+};
+
+int __init ovmf_log_probe(unsigned long ovmf_debug_log_table)
+{
+	int ret = -EINVAL;
+	u64 size;
+
+	/* map + verify header */
+	hdr = memremap(ovmf_debug_log_table, sizeof(*hdr), MEMREMAP_WB);
+	if (!hdr) {
+		pr_err("OVMF debug log: header map failed\n");
+		return -EINVAL;
+	}
+
+	if (hdr->magic1 != OVMF_DEBUG_LOG_MAGIC1 ||
+	    hdr->magic2 != OVMF_DEBUG_LOG_MAGIC2) {
+		printk(KERN_ERR "OVMF debug log: magic mismatch\n");
+		goto err_unmap;
+	}
+
+	size = hdr->hdr_size + hdr->log_size;
+	pr_info("OVMF debug log: firmware version: \"%s\"\n", hdr->fw_version);
+	pr_info("OVMF debug log: buffer size: %lluk\n", size / 1024);
+
+	/* map complete log buffer */
+	memunmap(hdr);
+	hdr = memremap(ovmf_debug_log_table, size, MEMREMAP_WB);
+	if (!hdr) {
+		pr_err("OVMF debug log: buffer map failed\n");
+		return -EINVAL;
+	}
+	logbuf = (void *)hdr + hdr->hdr_size;
+	logbufsize = hdr->log_size;
+
+	ovmf_log_bin_attr.size = size;
+	ret = sysfs_create_bin_file(efi_kobj, &ovmf_log_bin_attr);
+	if (ret != 0) {
+		pr_err("OVMF debug log: sysfs register failed\n");
+		goto err_unmap;
+	}
+
+	return 0;
+
+err_unmap:
+	memunmap(hdr);
+	return ret;
+}