From a26ca6ad4c4aa4afcbfe4c46c33ad98859736245 Mon Sep 17 00:00:00 2001
From: Tina Zhang <tina.zhang@intel.com>
Date: Sun, 11 Feb 2018 14:59:19 +0800
Subject: [PATCH] drm/i915/gvt: Support BAR0 8-byte reads/writes
Git-commit: a26ca6ad4c4aa4afcbfe4c46c33ad98859736245
Patch-mainline: v4.16-rc2
References: FATE#322643 bsc#1055900
GGTT is in BAR0 with 8 bytes aligned. With a qemu patch (commit:
38d49e8c1523d97d2191190d3f7b4ce7a0ab5aa3), VFIO can use 8-byte reads/
writes to access it.
This patch is to support the 8-byte GGTT reads/writes.
Ideally, we would like to support 8-byte reads/writes for the total BAR0.
But it needs more work for handling 8-byte MMIO reads/writes.
This patch can fix the issue caused by partial updating GGTT entry, during
guest booting up.
V3:
- Use intel_vgpu_get_bar_gpa() stead. (Zhenyu)
- Include all the GGTT checking logic in gtt_entry(). (Zhenyu)
V2:
- Limit to GGTT entry. (Zhenyu)
Signed-off-by: Tina Zhang <tina.zhang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpu/drm/i915/gvt/kvmgt.c | 51 +++++++++++++++++++++++++++++++++++++--
1 file changed, 49 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -733,6 +733,25 @@ static ssize_t intel_vgpu_rw(struct mdev
return ret == 0 ? count : ret;
}
+static bool gtt_entry(struct mdev_device *mdev, loff_t *ppos)
+{
+ struct intel_vgpu *vgpu = mdev_get_drvdata(mdev);
+ unsigned int index = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
+ struct intel_gvt *gvt = vgpu->gvt;
+ int offset;
+
+ /* Only allow MMIO GGTT entry access */
+ if (index != PCI_BASE_ADDRESS_0)
+ return false;
+
+ offset = (u64)(*ppos & VFIO_PCI_OFFSET_MASK) -
+ intel_vgpu_get_bar_gpa(vgpu, PCI_BASE_ADDRESS_0);
+
+ return (offset >= gvt->device_info.gtt_start_offset &&
+ offset < gvt->device_info.gtt_start_offset + gvt_ggtt_sz(gvt)) ?
+ true : false;
+}
+
static ssize_t intel_vgpu_read(struct mdev_device *mdev, char __user *buf,
size_t count, loff_t *ppos)
{
@@ -742,7 +761,21 @@ static ssize_t intel_vgpu_read(struct md
while (count) {
size_t filled;
- if (count >= 4 && !(*ppos % 4)) {
+ /* Only support GGTT entry 8 bytes read */
+ if (count >= 8 && !(*ppos % 8) &&
+ gtt_entry(mdev, ppos)) {
+ u64 val;
+
+ ret = intel_vgpu_rw(mdev, (char *)&val, sizeof(val),
+ ppos, false);
+ if (ret <= 0)
+ goto read_err;
+
+ if (copy_to_user(buf, &val, sizeof(val)))
+ goto read_err;
+
+ filled = 8;
+ } else if (count >= 4 && !(*ppos % 4)) {
u32 val;
ret = intel_vgpu_rw(mdev, (char *)&val, sizeof(val),
@@ -802,7 +835,21 @@ static ssize_t intel_vgpu_write(struct m
while (count) {
size_t filled;
- if (count >= 4 && !(*ppos % 4)) {
+ /* Only support GGTT entry 8 bytes write */
+ if (count >= 8 && !(*ppos % 8) &&
+ gtt_entry(mdev, ppos)) {
+ u64 val;
+
+ if (copy_from_user(&val, buf, sizeof(val)))
+ goto write_err;
+
+ ret = intel_vgpu_rw(mdev, (char *)&val, sizeof(val),
+ ppos, true);
+ if (ret <= 0)
+ goto write_err;
+
+ filled = 8;
+ } else if (count >= 4 && !(*ppos % 4)) {
u32 val;
if (copy_from_user(&val, buf, sizeof(val)))