[PATCH pre-squash 07/14] virtio_pci: macros for PCI layout offsets

From: Michael S. Tsirkin
Date: Wed Jan 21 2015 - 10:05:10 EST


From: Rusty Russell <rusty@xxxxxxxxxxxxxxx>

QEMU wants it, so why not? Trust, but verify.

Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Tested-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
---
include/uapi/linux/virtio_pci.h | 30 ++++++++++++++++++++
drivers/virtio/virtio_pci_modern.c | 58 +++++++++++++++++++++++++++++++++++++-
2 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
index a2b2e13..0911c62 100644
--- a/include/uapi/linux/virtio_pci.h
+++ b/include/uapi/linux/virtio_pci.h
@@ -160,6 +160,36 @@ struct virtio_pci_common_cfg {
__le32 queue_used_hi; /* read-write */
};

+/* Macro versions of offsets for the Old Timers! */
+#define VIRTIO_PCI_CAP_VNDR 0
+#define VIRTIO_PCI_CAP_NEXT 1
+#define VIRTIO_PCI_CAP_LEN 2
+#define VIRTIO_PCI_CAP_TYPE_AND_BAR 3
+#define VIRTIO_PCI_CAP_OFFSET 4
+#define VIRTIO_PCI_CAP_LENGTH 8
+
+#define VIRTIO_PCI_NOTIFY_CAP_MULT 12
+
+#define VIRTIO_PCI_COMMON_DFSELECT 0
+#define VIRTIO_PCI_COMMON_DF 4
+#define VIRTIO_PCI_COMMON_GFSELECT 8
+#define VIRTIO_PCI_COMMON_GF 12
+#define VIRTIO_PCI_COMMON_MSIX 16
+#define VIRTIO_PCI_COMMON_NUMQ 18
+#define VIRTIO_PCI_COMMON_STATUS 20
+#define VIRTIO_PCI_COMMON_CFGGENERATION 21
+#define VIRTIO_PCI_COMMON_Q_SELECT 22
+#define VIRTIO_PCI_COMMON_Q_SIZE 24
+#define VIRTIO_PCI_COMMON_Q_MSIX 26
+#define VIRTIO_PCI_COMMON_Q_ENABLE 28
+#define VIRTIO_PCI_COMMON_Q_NOFF 30
+#define VIRTIO_PCI_COMMON_Q_DESCLO 32
+#define VIRTIO_PCI_COMMON_Q_DESCHI 36
+#define VIRTIO_PCI_COMMON_Q_AVAILLO 40
+#define VIRTIO_PCI_COMMON_Q_AVAILHI 44
+#define VIRTIO_PCI_COMMON_Q_USEDLO 48
+#define VIRTIO_PCI_COMMON_Q_USEDHI 52
+
#endif /* VIRTIO_PCI_NO_MODERN */

#endif
diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index a3d8101..c86594e 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -464,9 +464,65 @@ static void virtio_pci_release_dev(struct device *_d)
kfree(vp_dev);
}

-/* TODO: validate the ABI statically. */
+/* This is part of the ABI. Don't screw with it. */
static inline void check_offsets(void)
{
+ /* Note: disk space was harmed in compilation of this function. */
+ BUILD_BUG_ON(VIRTIO_PCI_CAP_VNDR !=
+ offsetof(struct virtio_pci_cap, cap_vndr));
+ BUILD_BUG_ON(VIRTIO_PCI_CAP_NEXT !=
+ offsetof(struct virtio_pci_cap, cap_next));
+ BUILD_BUG_ON(VIRTIO_PCI_CAP_LEN !=
+ offsetof(struct virtio_pci_cap, cap_len));
+ BUILD_BUG_ON(VIRTIO_PCI_CAP_TYPE_AND_BAR !=
+ offsetof(struct virtio_pci_cap, type_and_bar));
+ BUILD_BUG_ON(VIRTIO_PCI_CAP_OFFSET !=
+ offsetof(struct virtio_pci_cap, offset));
+ BUILD_BUG_ON(VIRTIO_PCI_CAP_LENGTH !=
+ offsetof(struct virtio_pci_cap, length));
+ BUILD_BUG_ON(VIRTIO_PCI_NOTIFY_CAP_MULT !=
+ offsetof(struct virtio_pci_notify_cap,
+ notify_off_multiplier));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_DFSELECT !=
+ offsetof(struct virtio_pci_common_cfg,
+ device_feature_select));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_DF !=
+ offsetof(struct virtio_pci_common_cfg, device_feature));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_GFSELECT !=
+ offsetof(struct virtio_pci_common_cfg,
+ guest_feature_select));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_GF !=
+ offsetof(struct virtio_pci_common_cfg, guest_feature));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_MSIX !=
+ offsetof(struct virtio_pci_common_cfg, msix_config));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_NUMQ !=
+ offsetof(struct virtio_pci_common_cfg, num_queues));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_STATUS !=
+ offsetof(struct virtio_pci_common_cfg, device_status));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_CFGGENERATION !=
+ offsetof(struct virtio_pci_common_cfg, config_generation));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SELECT !=
+ offsetof(struct virtio_pci_common_cfg, queue_select));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SIZE !=
+ offsetof(struct virtio_pci_common_cfg, queue_size));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_MSIX !=
+ offsetof(struct virtio_pci_common_cfg, queue_msix_vector));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_ENABLE !=
+ offsetof(struct virtio_pci_common_cfg, queue_enable));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_NOFF !=
+ offsetof(struct virtio_pci_common_cfg, queue_notify_off));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCLO !=
+ offsetof(struct virtio_pci_common_cfg, queue_desc_lo));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCHI !=
+ offsetof(struct virtio_pci_common_cfg, queue_desc_hi));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILLO !=
+ offsetof(struct virtio_pci_common_cfg, queue_avail_lo));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILHI !=
+ offsetof(struct virtio_pci_common_cfg, queue_avail_hi));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDLO !=
+ offsetof(struct virtio_pci_common_cfg, queue_used_lo));
+ BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDHI !=
+ offsetof(struct virtio_pci_common_cfg, queue_used_hi));
}

/* the PCI probing function */
--
MST

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