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Message-Id: <20171031151938.14982-6-marcandre.lureau@redhat.com>
Date: Tue, 31 Oct 2017 16:19:38 +0100
From: Marc-André Lureau <marcandre.lureau@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: somlo@....edu, qemu-devel@...gnu.org, mst@...hat.com,
Marc-André Lureau <marcandre.lureau@...hat.com>
Subject: [PATCH v4 5/5] fw_cfg: write vmcoreinfo details
If the "etc/vmcoreinfo" fw_cfg file is present and we are not running
the kdump kernel, write the addr/size of the vmcoreinfo ELF note.
Signed-off-by: Marc-André Lureau <marcandre.lureau@...hat.com>
---
drivers/firmware/qemu_fw_cfg.c | 87 +++++++++++++++++++++++++++++++++++++++++-
1 file changed, 86 insertions(+), 1 deletion(-)
diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
index 8ce5e49b7c62..ebd9bb134900 100644
--- a/drivers/firmware/qemu_fw_cfg.c
+++ b/drivers/firmware/qemu_fw_cfg.c
@@ -35,6 +35,8 @@
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
+#include <linux/crash_core.h>
+#include <linux/crash_dump.h>
MODULE_AUTHOR("Gabriel L. Somlo <somlo@....edu>");
MODULE_DESCRIPTION("QEMU fw_cfg sysfs support");
@@ -59,6 +61,8 @@ MODULE_LICENSE("GPL");
/* fw_cfg "file name" is up to 56 characters (including terminating nul) */
#define FW_CFG_MAX_FILE_PATH 56
+#define VMCOREINFO_FORMAT_ELF 0x1
+
/* platform device for dma mapping */
static struct device *dev;
@@ -127,7 +131,8 @@ static ssize_t fw_cfg_dma_transfer(void *address, u32 length, u32 control)
dma_addr_t dma;
ssize_t ret = length;
enum dma_data_direction dir =
- (control & FW_CFG_DMA_CTL_READ ? DMA_FROM_DEVICE : 0);
+ (control & FW_CFG_DMA_CTL_READ ? DMA_FROM_DEVICE : 0) |
+ (control & FW_CFG_DMA_CTL_WRITE ? DMA_TO_DEVICE : 0);
if (address && length) {
dma_addr = dma_map_single(dev, address, length, dir);
@@ -225,6 +230,48 @@ static ssize_t fw_cfg_read_blob(u16 key,
return ret;
}
+#ifdef CONFIG_CRASH_CORE
+/* write chunk of given fw_cfg blob (caller responsible for sanity-check) */
+static ssize_t fw_cfg_write_blob(u16 key,
+ void *buf, loff_t pos, size_t count)
+{
+ u32 glk = -1U;
+ acpi_status status;
+ ssize_t ret = count;
+
+ /* If we have ACPI, ensure mutual exclusion against any potential
+ * device access by the firmware, e.g. via AML methods:
+ */
+ status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk);
+ if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) {
+ /* Should never get here */
+ WARN(1, "%s: Failed to lock ACPI!\n", __func__);
+ memset(buf, 0, count);
+ return -EBUSY;
+ }
+
+ mutex_lock(&fw_cfg_dev_lock);
+ if (pos == 0) {
+ ret = fw_cfg_dma_transfer(buf, count, key << 16
+ | FW_CFG_DMA_CTL_SELECT
+ | FW_CFG_DMA_CTL_WRITE);
+ } else {
+ iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl);
+ ret = fw_cfg_dma_transfer(0, pos, FW_CFG_DMA_CTL_SKIP);
+ if (ret < 0)
+ goto end;
+ ret = fw_cfg_dma_transfer(buf, count, FW_CFG_DMA_CTL_WRITE);
+ }
+
+end:
+ mutex_unlock(&fw_cfg_dev_lock);
+
+ acpi_release_global_lock(glk);
+
+ return ret;
+}
+#endif /* CONFIG_CRASH_CORE */
+
/* clean up fw_cfg device i/o */
static void fw_cfg_io_cleanup(void)
{
@@ -343,6 +390,37 @@ struct fw_cfg_sysfs_entry {
struct list_head list;
};
+#ifdef CONFIG_CRASH_CORE
+static ssize_t write_vmcoreinfo(const struct fw_cfg_file *f)
+{
+ struct vmci {
+ __le16 host_format;
+ __le16 guest_format;
+ __le32 size;
+ __le64 paddr;
+ } __packed;
+ struct vmci *data;
+ ssize_t ret;
+
+ data = kmalloc(sizeof(struct vmci), GFP_KERNEL | GFP_DMA);
+ if (!data)
+ return -ENOMEM;
+
+ /* spare ourself reading host format support for now since we
+ * don't know what else to format - host may ignore ours
+ */
+ *data = (struct vmci) {
+ .guest_format = cpu_to_le16(VMCOREINFO_FORMAT_ELF),
+ .size = cpu_to_le32(VMCOREINFO_NOTE_SIZE),
+ .paddr = cpu_to_le64(paddr_vmcoreinfo_note())
+ };
+ ret = fw_cfg_write_blob(f->select, data, 0, sizeof(struct vmci));
+
+ kfree(data);
+ return ret;
+}
+#endif /* CONFIG_CRASH_CORE */
+
/* get fw_cfg_sysfs_entry from kobject member */
static inline struct fw_cfg_sysfs_entry *to_entry(struct kobject *kobj)
{
@@ -582,6 +660,13 @@ static int fw_cfg_register_file(const struct fw_cfg_file *f)
int err;
struct fw_cfg_sysfs_entry *entry;
+#ifdef CONFIG_CRASH_CORE
+ if (strcmp(f->name, "etc/vmcoreinfo") == 0 && !is_kdump_kernel()) {
+ if (write_vmcoreinfo(f) < 0)
+ pr_warn("fw_cfg: failed to write vmcoreinfo");
+ }
+#endif
+
/* allocate new entry */
entry = kzalloc(sizeof(*entry), GFP_KERNEL);
if (!entry)
--
2.15.0.rc0.40.gaefcc5f6f
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