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Re: [Qemu-devel] Multi GPU passthrough via VFIO
From: |
Alex Williamson |
Subject: |
Re: [Qemu-devel] Multi GPU passthrough via VFIO |
Date: |
Fri, 07 Feb 2014 12:10:46 -0700 |
On Fri, 2014-02-07 at 01:22 +0100, Maik Broemme wrote:
> Interesting is the diff between 1st and 2nd boot, so if I do the lspci
> prior to the booting. The only difference between 1st start and 2nd
> start are:
>
> --- 001-lspci.290x.before.1st.log 2014-02-07 01:13:41.498827928 +0100
> +++ 004-lspci.290x.before.2nd.log 2014-02-07 01:16:50.966611282 +0100
> @@ -24,7 +24,7 @@
> ClockPM- Surprise- LLActRep- BwNot-
> LnkCtl: ASPM L0s L1 Enabled; RCB 64 bytes Disabled- CommClk+
> ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
> - LnkSta: Speed 5GT/s, Width x16, TrErr- Train- SlotClk+
> DLActive- BWMgmt- ABWMgmt-
> + LnkSta: Speed 2.5GT/s, Width x1, TrErr- Train- SlotClk+
> DLActive- BWMgmt- ABWMgmt-
> DevCap2: Completion Timeout: Not Supported, TimeoutDis-, LTR-,
> OBFF Not Supported
> DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR-,
> OBFF Disabled
> LnkCtl2: Target Link Speed: 8GT/s, EnterCompliance- SpeedDis-
> @@ -33,13 +33,13 @@
> LnkSta2: Current De-emphasis Level: -3.5dB,
> EqualizationComplete-, EqualizationPhase1-
> EqualizationPhase2-, EqualizationPhase3-,
> LinkEqualizationRequest-
> Capabilities: [a0] MSI: Enable- Count=1/1 Maskable- 64bit+
> - Address: 0000000000000000 Data: 0000
> + Address: 00000000fee00000 Data: 0000
> Capabilities: [100 v1] Vendor Specific Information: ID=0001 Rev=1
> Len=010 <?>
> Capabilities: [150 v2] Advanced Error Reporting
> UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt-
> RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
> UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt-
> RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
> UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt-
> RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
> - CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr-
> + CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+
> CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+
> AERCap: First Error Pointer: 00, GenCap+ CGenEn- ChkCap+ ChkEn-
> Capabilities: [270 v1] #19
>
> After that if I do suspend-to-ram / resume trick I have again lspci
> output from before 1st boot.
The Link Status change after X is stopped seems the most interesting to
me. The MSI change is probably explained by the MSI save/restore of the
device, but should be harmless since MSI is disabled. I'm a bit
surprised the Correctable Error Status in the AER capability didn't get
cleared. I would have thought that a bus reset would have caused the
link to retrain back to the original speed/width as well. Let's check
that we're actually getting a bus reset, try this in addition to the
previous qemu patch. This just enables debug logging for the bus resest
function. Thanks,
Alex
diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
index 8db182f..7fec259 100644
--- a/hw/misc/vfio.c
+++ b/hw/misc/vfio.c
@@ -2927,6 +2927,10 @@ static bool vfio_pci_host_match(PCIHostDeviceAddress *hos
host1->slot == host2->slot && host1->function == host2->function);
}
+#undef DPRINTF
+#define DPRINTF(fmt, ...) \
+ do { fprintf(stderr, "vfio: " fmt, ## __VA_ARGS__); } while (0)
+
static int vfio_pci_hot_reset(VFIODevice *vdev, bool single)
{
VFIOGroup *group;
@@ -3104,6 +3108,15 @@ out_single:
return ret;
}
+#undef DPRINTF
+#ifdef DEBUG_VFIO
+#define DPRINTF(fmt, ...) \
+ do { fprintf(stderr, "vfio: " fmt, ## __VA_ARGS__); } while (0)
+#else
+#define DPRINTF(fmt, ...) \
+ do { } while (0)
+#endif
+
/*
* We want to differentiate hot reset of mulitple in-use devices vs hot reset
* of a single in-use device. VFIO_DEVICE_RESET will already handle the case
- [Qemu-devel] Multi GPU passthrough via VFIO, Maik Broemme, 2014/02/05
- Re: [Qemu-devel] Multi GPU passthrough via VFIO, Alex Williamson, 2014/02/05
- Re: [Qemu-devel] Multi GPU passthrough via VFIO, Maik Broemme, 2014/02/05
- Re: [Qemu-devel] Multi GPU passthrough via VFIO, Alex Williamson, 2014/02/05
- Re: [Qemu-devel] Multi GPU passthrough via VFIO, Maik Broemme, 2014/02/05
- Re: [Qemu-devel] Multi GPU passthrough via VFIO, Maik Broemme, 2014/02/05
- Re: [Qemu-devel] Multi GPU passthrough via VFIO, Alex Williamson, 2014/02/05
- Re: [Qemu-devel] Multi GPU passthrough via VFIO, Maik Broemme, 2014/02/06
- Re: [Qemu-devel] Multi GPU passthrough via VFIO, Maik Broemme, 2014/02/07
- Re: [Qemu-devel] Multi GPU passthrough via VFIO,
Alex Williamson <=
- Re: [Qemu-devel] Multi GPU passthrough via VFIO, Maik Broemme, 2014/02/07
- Re: [Qemu-devel] Multi GPU passthrough via VFIO, Maik Broemme, 2014/02/13
- Re: [Qemu-devel] Multi GPU passthrough via VFIO, Alex Williamson, 2014/02/13
- Re: [Qemu-devel] Multi GPU passthrough via VFIO, Maik Broemme, 2014/02/14