[PATCH v4] drm/i915/gvt: introduced failsafe mode into vgpu
Min He
min.he at intel.com
Fri Feb 17 01:39:53 UTC 2017
New failsafe mode is introduced, when we detect guest not supporting
GVT-g.
In failsafe mode, we will ignore all the MMIO and cfg space read/write
from guest.
This patch can fix the issue that when guest kernel or graphics driver
version is too low, there will be a lot of kernel traces in host.
V4: changed coding style by Zhenyu and Ping's advice
V3: modified coding style and error messages according to Zhenyu's comment
V2: 1) implemented MMIO/GTT/WP pages read/write logic; 2) used a unified
function to enter failsafe mode
Signed-off-by: Min He <min.he at intel.com>
Signed-off-by: Pei Zhang <pei.zhang at intel.com>
---
drivers/gpu/drm/i915/gvt/cfg_space.c | 3 ++
drivers/gpu/drm/i915/gvt/gvt.h | 6 ++++
drivers/gpu/drm/i915/gvt/handlers.c | 36 +++++++++++++++++++++
drivers/gpu/drm/i915/gvt/mmio.c | 62 ++++++++++++++++++++++++++++++++++++
drivers/gpu/drm/i915/gvt/vgpu.c | 6 +++-
5 files changed, 112 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gvt/cfg_space.c b/drivers/gpu/drm/i915/gvt/cfg_space.c
index 4a6a2ed..a77e050 100644
--- a/drivers/gpu/drm/i915/gvt/cfg_space.c
+++ b/drivers/gpu/drm/i915/gvt/cfg_space.c
@@ -237,6 +237,9 @@ int intel_vgpu_emulate_cfg_write(struct intel_vgpu *vgpu, unsigned int offset,
{
int ret;
+ if (vgpu->failsafe)
+ return 0;
+
if (WARN_ON(bytes > 4))
return -EINVAL;
diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
index e227caf..778f396 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.h
+++ b/drivers/gpu/drm/i915/gvt/gvt.h
@@ -143,6 +143,8 @@ struct intel_vgpu {
int id;
unsigned long handle; /* vGPU handle used by hypervisor MPT modules */
bool active;
+ bool pv_notified;
+ bool failsafe;
bool resetting;
void *sched_data;
@@ -449,6 +451,10 @@ struct intel_gvt_ops {
};
+enum {
+ GVT_FAILSAFE_UNSUPPORTED_GUEST,
+};
+
#include "mpt.h"
#endif
diff --git a/drivers/gpu/drm/i915/gvt/handlers.c b/drivers/gpu/drm/i915/gvt/handlers.c
index 1d45062..6f098bb 100644
--- a/drivers/gpu/drm/i915/gvt/handlers.c
+++ b/drivers/gpu/drm/i915/gvt/handlers.c
@@ -150,10 +150,34 @@ static int render_mmio_to_ring_id(struct intel_gvt *gvt, unsigned int reg)
#define fence_num_to_offset(num) \
(num * 8 + i915_mmio_reg_offset(FENCE_REG_GEN6_LO(0)))
+
+static void enter_failsafe_mode(struct intel_vgpu *vgpu, int reason)
+{
+ switch (reason) {
+ case GVT_FAILSAFE_UNSUPPORTED_GUEST:
+ pr_err("Detected your guest driver doesn't support GVT-g.\n");
+ break;
+ default:
+ break;
+ }
+ pr_err("Now vgpu %d will enter failsafe mode.\n", vgpu->id);
+ vgpu->failsafe = true;
+}
+
static int sanitize_fence_mmio_access(struct intel_vgpu *vgpu,
unsigned int fence_num, void *p_data, unsigned int bytes)
{
if (fence_num >= vgpu_fence_sz(vgpu)) {
+
+ /* When guest access oob fence regs without access
+ * pv_info first, we treat guest not supporting GVT,
+ * and we will let vgpu enter failsafe mode.
+ */
+ if (!vgpu->pv_notified) {
+ enter_failsafe_mode(vgpu,
+ GVT_FAILSAFE_UNSUPPORTED_GUEST);
+ return -EINVAL;
+ }
gvt_err("vgpu%d: found oob fence register access\n",
vgpu->id);
gvt_err("vgpu%d: total fence num %d access fence num %d\n",
@@ -1001,6 +1025,7 @@ static int pvinfo_mmio_read(struct intel_vgpu *vgpu, unsigned int offset,
if (invalid_read)
gvt_err("invalid pvinfo read: [%x:%x] = %x\n",
offset, bytes, *(u32 *)p_data);
+ vgpu->pv_notified = true;
return 0;
}
@@ -1318,6 +1343,17 @@ static int ring_mode_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
bool enable_execlist;
write_vreg(vgpu, offset, p_data, bytes);
+
+ /* when PPGTT mode enabled, we will check if guest has called
+ * pvinfo, if not, we will treat this guest as non-gvtg-aware
+ * guest, and stop emulating its cfg space, mmio, gtt, etc.
+ */
+ if (((data & _MASKED_BIT_ENABLE(GFX_PPGTT_ENABLE)) ||
+ (data & _MASKED_BIT_ENABLE(GFX_RUN_LIST_ENABLE)))
+ && !vgpu->pv_notified) {
+ enter_failsafe_mode(vgpu, GVT_FAILSAFE_UNSUPPORTED_GUEST);
+ return 0;
+ }
if ((data & _MASKED_BIT_ENABLE(GFX_RUN_LIST_ENABLE))
|| (data & _MASKED_BIT_DISABLE(GFX_RUN_LIST_ENABLE))) {
enable_execlist = !!(data & GFX_RUN_LIST_ENABLE);
diff --git a/drivers/gpu/drm/i915/gvt/mmio.c b/drivers/gpu/drm/i915/gvt/mmio.c
index 4df078b..b2d72da 100644
--- a/drivers/gpu/drm/i915/gvt/mmio.c
+++ b/drivers/gpu/drm/i915/gvt/mmio.c
@@ -57,6 +57,58 @@ int intel_vgpu_gpa_to_mmio_offset(struct intel_vgpu *vgpu, u64 gpa)
(reg >= gvt->device_info.gtt_start_offset \
&& reg < gvt->device_info.gtt_start_offset + gvt_ggtt_sz(gvt))
+static void failsafe_emulate_mmio_rw(struct intel_vgpu *vgpu, uint64_t pa,
+ void *p_data, unsigned int bytes, bool read)
+{
+ struct intel_gvt *gvt = NULL;
+ void *pt = NULL;
+ unsigned int offset = 0;
+
+ if (!vgpu || !p_data)
+ return;
+
+ gvt = vgpu->gvt;
+ mutex_lock(&gvt->lock);
+ offset = intel_vgpu_gpa_to_mmio_offset(vgpu, pa);
+ if (reg_is_mmio(gvt, offset)) {
+ if (read)
+ intel_vgpu_default_mmio_read(vgpu, offset, p_data,
+ bytes);
+ else
+ intel_vgpu_default_mmio_write(vgpu, offset, p_data,
+ bytes);
+ } else if (reg_is_gtt(gvt, offset) &&
+ vgpu->gtt.ggtt_mm->virtual_page_table) {
+ offset -= gvt->device_info.gtt_start_offset;
+ pt = vgpu->gtt.ggtt_mm->virtual_page_table + offset;
+ if (read)
+ memcpy(p_data, pt, bytes);
+ else
+ memcpy(pt, p_data, bytes);
+
+ } else if (atomic_read(&vgpu->gtt.n_write_protected_guest_page)) {
+ struct intel_vgpu_guest_page *gp;
+
+ /* Since we enter the failsafe mode early during guest boot,
+ * guest may not have chance to set up its ppgtt table, so
+ * there should not be any wp pages for guest. Keep the wp
+ * related code here in case we need to handle it in furture.
+ */
+ gp = intel_vgpu_find_guest_page(vgpu, pa >> PAGE_SHIFT);
+ if (gp) {
+ /* remove write protection to prevent furture traps */
+ intel_vgpu_clean_guest_page(vgpu, gp);
+ if (read)
+ intel_gvt_hypervisor_read_gpa(vgpu, pa,
+ p_data, bytes);
+ else
+ intel_gvt_hypervisor_write_gpa(vgpu, pa,
+ p_data, bytes);
+ }
+ }
+ mutex_unlock(&gvt->lock);
+}
+
/**
* intel_vgpu_emulate_mmio_read - emulate MMIO read
* @vgpu: a vGPU
@@ -75,6 +127,11 @@ int intel_vgpu_emulate_mmio_read(struct intel_vgpu *vgpu, uint64_t pa,
unsigned int offset = 0;
int ret = -EINVAL;
+
+ if (vgpu->failsafe) {
+ failsafe_emulate_mmio_rw(vgpu, pa, p_data, bytes, true);
+ return 0;
+ }
mutex_lock(&gvt->lock);
if (atomic_read(&vgpu->gtt.n_write_protected_guest_page)) {
@@ -188,6 +245,11 @@ int intel_vgpu_emulate_mmio_write(struct intel_vgpu *vgpu, uint64_t pa,
u32 old_vreg = 0, old_sreg = 0;
int ret = -EINVAL;
+ if (vgpu->failsafe) {
+ failsafe_emulate_mmio_rw(vgpu, pa, p_data, bytes, false);
+ return 0;
+ }
+
mutex_lock(&gvt->lock);
if (atomic_read(&vgpu->gtt.n_write_protected_guest_page)) {
diff --git a/drivers/gpu/drm/i915/gvt/vgpu.c b/drivers/gpu/drm/i915/gvt/vgpu.c
index 67d471c..6c9b440 100644
--- a/drivers/gpu/drm/i915/gvt/vgpu.c
+++ b/drivers/gpu/drm/i915/gvt/vgpu.c
@@ -386,8 +386,12 @@ void intel_gvt_reset_vgpu_locked(struct intel_vgpu *vgpu, bool dmlr,
intel_vgpu_reset_mmio(vgpu);
populate_pvinfo_page(vgpu);
- if (dmlr)
+ if (dmlr) {
intel_vgpu_reset_cfg_space(vgpu);
+ /* only reset the failsafe mode when dmlr reset */
+ vgpu->failsafe = false;
+ vgpu->pv_notified = false;
+ }
}
vgpu->resetting = false;
--
1.9.1
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