[Intel-wired-lan] [PATCH AUTOSEL 6.17] ixgbe: handle IXGBE_VF_FEATURES_NEGOTIATE mbox cmd
Sasha Levin
sashal at kernel.org
Tue Oct 28 00:39:05 UTC 2025
From: Jedrzej Jagielski <jedrzej.jagielski at intel.com>
[ Upstream commit 823be089f9c8ab136ba382b516aedd3f7ac854bd ]
Send to VF information about features supported by the PF driver.
Increase API version to 1.7.
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel at intel.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov at intel.com>
Signed-off-by: Jedrzej Jagielski <jedrzej.jagielski at intel.com>
Tested-by: Rafal Romanowski <rafal.romanowski at intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller at intel.com>
Link: https://patch.msgid.link/20251009-jk-iwl-net-2025-10-01-v3-5-ef32a425b92a@intel.com
Signed-off-by: Jakub Kicinski <kuba at kernel.org>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
LLM Generated explanations, may be completely bogus:
Based on my analysis using semantic code analysis tools and git history
examination, here is my determination:
**Answer: YES**
**Extensive Explanation:**
## 1. Analysis Performed Using Semantic Tools
I used the following semantic code analysis tools to examine this
commit:
- **mcp__semcode__find_function**: Located `ixgbe_rcv_msg_from_vf()`,
`ixgbe_negotiate_vf_api()`, and `ixgbe_msg_task()` to understand the
mailbox message handling flow
- **mcp__semcode__find_callers**: Traced the call chain:
`ixgbe_msix_other()` (IRQ handler) → `ixgbe_msg_task()` →
`ixgbe_rcv_msg_from_vf()`, confirming this code is triggered by VF
interrupts
- **Git tools**: Examined commit history, found companion VF-side fix
(a7075f501bd33), and traced the problematic commits back to v4.20
## 2. Code Changes Analysis
The commit adds:
- **New API version**: `ixgbe_mbox_api_17` (line 56 in ixgbe_mbx.h)
- **New mailbox command**: `IXGBE_VF_FEATURES_NEGOTIATE` (0x12) for VF-
to-PF feature negotiation
- **Feature flags**: `IXGBEVF_PF_SUP_IPSEC` and `IXGBEVF_PF_SUP_ESX_MBX`
to indicate PF capabilities
- **New handler function**: `ixgbe_negotiate_vf_features()` at
drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c:1268
- **Case statement addition**: Adds handling for the new mailbox command
in `ixgbe_rcv_msg_from_vf()`
- **API version updates**: Adds `ixgbe_mbox_api_17` cases to 8 existing
switch statements for backward compatibility
## 3. Impact Scope (from semantic analysis)
**Call graph analysis** shows:
- 1 direct caller of `ixgbe_rcv_msg_from_vf()`: the `ixgbe_msg_task()`
function
- User-space can trigger this code path through SR-IOV VF operations
- The code runs in interrupt context (from MSI-X handler)
- Affects all SR-IOV deployments using ixgbe PF with ixgbevf VF drivers
## 4. This Is a Bug Fix, Not a New Feature
The companion VF-side commit (a7075f501bd33) clearly indicates this is a
**critical bug fix**:
```
Fixes: 0062e7cc955e ("ixgbevf: add VF IPsec offload code")
Fixes: 339f28964147 ("ixgbevf: Add support for new mailbox communication
between PF and VF")
Cc: stable at vger.kernel.org
```
The VF commit message explains:
- "API 1.6 cannot be supported for Linux ixgbe driver as it causes
**crashes**"
- Backward compatibility was broken since API 1.4 (introduced in v4.20,
August 2018)
- VF drivers attempting to use IPsec or ESX mailbox features crash when
PF doesn't support them
- No negotiation mechanism existed, causing interoperability failures
between Linux/ESX/FreeBSD drivers
## 5. Why This Must Be Backported
**Critical reasons:**
1. **Fixes crashes**: VFs crash when attempting to use features not
supported by the PF
(drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c:1268-1282)
2. **Paired fix**: The VF-side fix (a7075f501bd33) has explicit "Cc:
stable at vger.kernel.org" tag and is already being backported (as
evidenced by commit a376e29b1b196 showing "commit a7075f501bd33
upstream")
3. **Incomplete without both sides**: The VF asks "what features do you
support?" but the PF needs this commit to answer. Without the PF
handler, VF gets -EOPNOTSUPP, defeating the fix
4. **Affects all kernels ≥ v4.20**: The problematic commits exist in all
kernels from v4.20 onwards (confirmed via `git tag --contains
0062e7cc955e`)
5. **Small, contained change**: Only adds 47 lines across 2 files,
focused on one specific mailbox command
## 6. Compliance with Stable Tree Rules
**Passes all stable tree criteria:**
- ✅ Fixes important bug (crashes in SR-IOV scenarios)
- ✅ Small and obviously correct (adds one mailbox handler)
- ✅ No architectural changes (extends existing switch/case pattern)
- ✅ Minimal regression risk (only affects new API 1.7, old APIs
unchanged)
- ✅ Companion to explicit stable-tagged commit (a7075f501bd33)
- ✅ Already tested (Tested-by: Rafal Romanowski tag)
## 7. Dependency Check
The commit depends on:
- `ixgbe_send_vf_link_status()` function (added in f7f97cbc03a47, which
immediately precedes this commit in the series)
- Standard ixgbe mailbox infrastructure (present in all affected
kernels)
**Recommendation**: Backport as part of the series with its VF
counterpart and the link status fix.
drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h | 10 +++++
.../net/ethernet/intel/ixgbe/ixgbe_sriov.c | 37 +++++++++++++++++++
2 files changed, 47 insertions(+)
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h
index f7256a339c99b..0334ed4b8fa39 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h
@@ -52,6 +52,7 @@ enum ixgbe_pfvf_api_rev {
ixgbe_mbox_api_14, /* API version 1.4, linux/freebsd VF driver */
ixgbe_mbox_api_15, /* API version 1.5, linux/freebsd VF driver */
ixgbe_mbox_api_16, /* API version 1.6, linux/freebsd VF driver */
+ ixgbe_mbox_api_17, /* API version 1.7, linux/freebsd VF driver */
/* This value should always be last */
ixgbe_mbox_api_unknown, /* indicates that API version is not known */
};
@@ -91,6 +92,9 @@ enum ixgbe_pfvf_api_rev {
/* mailbox API, version 1.6 VF requests */
#define IXGBE_VF_GET_PF_LINK_STATE 0x11 /* request PF to send link info */
+/* mailbox API, version 1.7 VF requests */
+#define IXGBE_VF_FEATURES_NEGOTIATE 0x12 /* get features supported by PF */
+
/* length of permanent address message returned from PF */
#define IXGBE_VF_PERMADDR_MSG_LEN 4
/* word in permanent address message with the current multicast type */
@@ -101,6 +105,12 @@ enum ixgbe_pfvf_api_rev {
#define IXGBE_VF_MBX_INIT_TIMEOUT 2000 /* number of retries on mailbox */
#define IXGBE_VF_MBX_INIT_DELAY 500 /* microseconds between retries */
+/* features negotiated between PF/VF */
+#define IXGBEVF_PF_SUP_IPSEC BIT(0)
+#define IXGBEVF_PF_SUP_ESX_MBX BIT(1)
+
+#define IXGBE_SUPPORTED_FEATURES IXGBEVF_PF_SUP_IPSEC
+
struct ixgbe_hw;
int ixgbe_read_mbx(struct ixgbe_hw *, u32 *, u16, u16);
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
index b09271d61a4ef..ee133d6749b37 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
@@ -511,6 +511,7 @@ static int ixgbe_set_vf_lpe(struct ixgbe_adapter *adapter, u32 max_frame, u32 vf
case ixgbe_mbox_api_13:
case ixgbe_mbox_api_14:
case ixgbe_mbox_api_16:
+ case ixgbe_mbox_api_17:
/* Version 1.1 supports jumbo frames on VFs if PF has
* jumbo frames enabled which means legacy VFs are
* disabled
@@ -1048,6 +1049,7 @@ static int ixgbe_negotiate_vf_api(struct ixgbe_adapter *adapter,
case ixgbe_mbox_api_13:
case ixgbe_mbox_api_14:
case ixgbe_mbox_api_16:
+ case ixgbe_mbox_api_17:
adapter->vfinfo[vf].vf_api = api;
return 0;
default:
@@ -1075,6 +1077,7 @@ static int ixgbe_get_vf_queues(struct ixgbe_adapter *adapter,
case ixgbe_mbox_api_13:
case ixgbe_mbox_api_14:
case ixgbe_mbox_api_16:
+ case ixgbe_mbox_api_17:
break;
default:
return -1;
@@ -1115,6 +1118,7 @@ static int ixgbe_get_vf_reta(struct ixgbe_adapter *adapter, u32 *msgbuf, u32 vf)
/* verify the PF is supporting the correct API */
switch (adapter->vfinfo[vf].vf_api) {
+ case ixgbe_mbox_api_17:
case ixgbe_mbox_api_16:
case ixgbe_mbox_api_14:
case ixgbe_mbox_api_13:
@@ -1149,6 +1153,7 @@ static int ixgbe_get_vf_rss_key(struct ixgbe_adapter *adapter,
/* verify the PF is supporting the correct API */
switch (adapter->vfinfo[vf].vf_api) {
+ case ixgbe_mbox_api_17:
case ixgbe_mbox_api_16:
case ixgbe_mbox_api_14:
case ixgbe_mbox_api_13:
@@ -1180,6 +1185,7 @@ static int ixgbe_update_vf_xcast_mode(struct ixgbe_adapter *adapter,
case ixgbe_mbox_api_13:
case ixgbe_mbox_api_14:
case ixgbe_mbox_api_16:
+ case ixgbe_mbox_api_17:
break;
default:
return -EOPNOTSUPP;
@@ -1251,6 +1257,7 @@ static int ixgbe_get_vf_link_state(struct ixgbe_adapter *adapter,
case ixgbe_mbox_api_13:
case ixgbe_mbox_api_14:
case ixgbe_mbox_api_16:
+ case ixgbe_mbox_api_17:
break;
default:
return -EOPNOTSUPP;
@@ -1278,6 +1285,7 @@ static int ixgbe_send_vf_link_status(struct ixgbe_adapter *adapter,
switch (adapter->vfinfo[vf].vf_api) {
case ixgbe_mbox_api_16:
+ case ixgbe_mbox_api_17:
if (hw->mac.type != ixgbe_mac_e610)
return -EOPNOTSUPP;
break;
@@ -1293,6 +1301,32 @@ static int ixgbe_send_vf_link_status(struct ixgbe_adapter *adapter,
return 0;
}
+/**
+ * ixgbe_negotiate_vf_features - negotiate supported features with VF driver
+ * @adapter: pointer to adapter struct
+ * @msgbuf: pointer to message buffers
+ * @vf: VF identifier
+ *
+ * Return: 0 on success or -EOPNOTSUPP when operation is not supported.
+ */
+static int ixgbe_negotiate_vf_features(struct ixgbe_adapter *adapter,
+ u32 *msgbuf, u32 vf)
+{
+ u32 features = msgbuf[1];
+
+ switch (adapter->vfinfo[vf].vf_api) {
+ case ixgbe_mbox_api_17:
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ features &= IXGBE_SUPPORTED_FEATURES;
+ msgbuf[1] = features;
+
+ return 0;
+}
+
static int ixgbe_rcv_msg_from_vf(struct ixgbe_adapter *adapter, u32 vf)
{
u32 mbx_size = IXGBE_VFMAILBOX_SIZE;
@@ -1370,6 +1404,9 @@ static int ixgbe_rcv_msg_from_vf(struct ixgbe_adapter *adapter, u32 vf)
case IXGBE_VF_GET_PF_LINK_STATE:
retval = ixgbe_send_vf_link_status(adapter, msgbuf, vf);
break;
+ case IXGBE_VF_FEATURES_NEGOTIATE:
+ retval = ixgbe_negotiate_vf_features(adapter, msgbuf, vf);
+ break;
default:
e_err(drv, "Unhandled Msg %8.8x\n", msgbuf[0]);
retval = -EIO;
--
2.51.0
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