Bug 1972056

Hi Meirav,

Thanks you file issue out, I have a few basic questions about this new feature:

1) How can I connect the fwcfg64 device to a vm through qemu command line(I tried this command "-fw_cfg name=opt/com.name.domain.your.example,string=1", but booted up vm failed, it seems it's wrong)? 
2) And in the vm, how to check the device's function?
3) If this device support hotpug/unplug?
4) When we do vm migration test, if will touch this driver's codes?

Thanks a lot~
Peixiu

(In reply to Peixiu Hou from comment #2)
> Hi Meirav,
> 
> Thanks you file issue out, I have a few basic questions about this new
> feature:
> 
> 1) How can I connect the fwcfg64 device to a vm through qemu command line(I
> tried this command "-fw_cfg name=opt/com.name.domain.your.example,string=1",
> but booted up vm failed, it seems it's wrong)? 
> 2) And in the vm, how to check the device's function?
> 3) If this device support hotpug/unplug?
> 4) When we do vm migration test, if will touch this driver's codes?
> 
> Thanks a lot~
> Peixiu

Hi Peixiu,
fwcfg64 is a quite new feature. 
Give me some time to find the answers.

Best regards,
Vadim.

(In reply to Vadim Rozenfeld from comment #3)
> (In reply to Peixiu Hou from comment #2)
> > Hi Meirav,
> > 
> > Thanks you file issue out, I have a few basic questions about this new
> > feature:
> > 
> > 1) How can I connect the fwcfg64 device to a vm through qemu command line(I
> > tried this command "-fw_cfg name=opt/com.name.domain.your.example,string=1",
> > but booted up vm failed, it seems it's wrong)? 

Run VM with "-device=vmcoreinfo" option (currently only x64 version seems to be working 
properly even thoug that x86 version is also included ito the build)


> > 2) And in the vm, how to check the device's function?
Inside of VM install fwcfgdmp.sys driver ( I use devcon for this) 
After installation you should see QEMU FwCfg Device" under "System Devices" category in
Device Manager Dialog.
Next, from the qemu monitor run "dump-guest-memory -w memory.dmp". Upon completion this 
command you should be able to open memory.dmp file with WinDbg as a normal crash dump file,
generated during BSOD processing.

> > 3) If this device support hotpug/unplug?
I'm quite sure that it doesn't. This device is in ACPI space. 

> > 4) When we do vm migration test, if will touch this driver's codes?

Migration should work AFAIU, hoverer it is not possible to create a memory dump during migration. 

> > 
> > Thanks a lot~
> > Peixiu
> 
> Hi Peixiu,
> fwcfg64 is a quite new feature. 
> Give me some time to find the answers.
> 
> Best regards,
> Vadim.

(In reply to Vadim Rozenfeld from comment #4)
> (In reply to Vadim Rozenfeld from comment #3)
> > (In reply to Peixiu Hou from comment #2)
> > > Hi Meirav,
> > > 
> > > Thanks you file issue out, I have a few basic questions about this new
> > > feature:
> > > 
> > > 1) How can I connect the fwcfg64 device to a vm through qemu command line(I
> > > tried this command "-fw_cfg name=opt/com.name.domain.your.example,string=1",
> > > but booted up vm failed, it seems it's wrong)? 
> 
> Run VM with "-device=vmcoreinfo" option (currently only x64 version seems to
> be working 
> properly even thoug that x86 version is also included ito the build)
> 
> 
> > > 2) And in the vm, how to check the device's function?
> Inside of VM install fwcfgdmp.sys driver ( I use devcon for this) 
> After installation you should see QEMU FwCfg Device" under "System Devices"
> category in
> Device Manager Dialog.
> Next, from the qemu monitor run "dump-guest-memory -w memory.dmp". Upon
> completion this 
> command you should be able to open memory.dmp file with WinDbg as a normal
> crash dump file,
> generated during BSOD processing.
> 

Hi Vadim,

Thanks a lot for your answer, I tested on win10-64 and win2019 guest vm, the device works well.

Used version:
RHEL9:
kernel-5.13.0-0.rc7.51.el9.x86_64
qemu-kvm-6.0.0-2.el9.x86_64
seabios-bin-1.14.0-4.el9.noarch
virtio-win-prewhql-202

RHEL8.5.0:
kernel-4.18.0-316.el8.x86_64
qemu-kvm-6.0.50-20.scrmod+el8.5.0+11566+2ca95551.wrb210623.x86_64
seabios-1.14.0-1.scrmod+el8.5.0+11566+2ca95551.x86_64
virtio-win-prewhql-202

And I also have some another questions want to confirm:
Q1: It seems this feature only support on windows guest? could you help to confirm it? thanks~

Q2: Yes, I tried test on win8.1-32 guest, the fwcfg driver can be installed successfully, but command dump-guest-memory hit error message as follows：
 (qemu) dump-guest-memory -w mem-8132.dmp
 Error: win-dump: invalid header, expected 'DU64', got 'DUMP'
If this feature will support on both windows x86_64 and windows i386 guest os in the future? 

Q3: I plan follows tests for this feature, could you help to review it?
1) Whql tests with "QEMU FwCfg Device".

2) Function test with fwcfg64 driver:
1. Do basic function test with fwcfg64 driver.
   step1: Boot a guest with "-device=vmcoreinfo" option
   step2: Install fwcfg64 driver in guest vm
   step3: Trigger a BSOD through "nmi"
   step4: Run "dump-guest-memory -w memory.dmp" in qemu monitor
   step5: Check the memory.dmp can be open with windb tools
2. Do system reboot/ system shutdown test with fwcfg device.
3. Do fwcfg driver install/uninstall test.
4. Use signtool.exe to check whether the driver is digital signed 

Thanks a lot~
Peixiu

(In reply to Peixiu Hou from comment #5)
> (In reply to Vadim Rozenfeld from comment #4)
> > (In reply to Vadim Rozenfeld from comment #3)
> > > (In reply to Peixiu Hou from comment #2)
> > > > Hi Meirav,
> > > > 
> > > > Thanks you file issue out, I have a few basic questions about this new
> > > > feature:
> > > > 
> > > > 1) How can I connect the fwcfg64 device to a vm through qemu command line(I
> > > > tried this command "-fw_cfg name=opt/com.name.domain.your.example,string=1",
> > > > but booted up vm failed, it seems it's wrong)? 
> > 
> > Run VM with "-device=vmcoreinfo" option (currently only x64 version seems to
> > be working 
> > properly even thoug that x86 version is also included ito the build)
> > 
> > 
> > > > 2) And in the vm, how to check the device's function?
> > Inside of VM install fwcfgdmp.sys driver ( I use devcon for this) 
> > After installation you should see QEMU FwCfg Device" under "System Devices"
> > category in
> > Device Manager Dialog.
> > Next, from the qemu monitor run "dump-guest-memory -w memory.dmp". Upon
> > completion this 
> > command you should be able to open memory.dmp file with WinDbg as a normal
> > crash dump file,
> > generated during BSOD processing.
> > 
> 
> Hi Vadim,
> 
> Thanks a lot for your answer, I tested on win10-64 and win2019 guest vm, the
> device works well.
> 
> Used version:
> RHEL9:
> kernel-5.13.0-0.rc7.51.el9.x86_64
> qemu-kvm-6.0.0-2.el9.x86_64
> seabios-bin-1.14.0-4.el9.noarch
> virtio-win-prewhql-202
> 
> RHEL8.5.0:
> kernel-4.18.0-316.el8.x86_64
> qemu-kvm-6.0.50-20.scrmod+el8.5.0+11566+2ca95551.wrb210623.x86_64
> seabios-1.14.0-1.scrmod+el8.5.0+11566+2ca95551.x86_64
> virtio-win-prewhql-202
> 
> And I also have some another questions want to confirm:
> Q1: It seems this feature only support on windows guest? could you help to
> confirm it? thanks~
> 
> Q2: Yes, I tried test on win8.1-32 guest, the fwcfg driver can be installed
> successfully, but command dump-guest-memory hit error message as follows：
>  (qemu) dump-guest-memory -w mem-8132.dmp

"-w" is for windows windbg 
dump-guest-memory command should work for linux guests but it is out the scope of
this bug.

>  Error: win-dump: invalid header, expected 'DU64', got 'DUMP'
> If this feature will support on both windows x86_64 and windows i386 guest
> os in the future? 
> 
That's true. 32-bit quests are not supported yet, and we need to clarify 
if they need to be supported, because adding support for 32-bit quest will
require some work from the quest driver side and may require some changes at 
qemu side.


> Q3: I plan follows tests for this feature, could you help to review it?
> 1) Whql tests with "QEMU FwCfg Device".
> 
> 2) Function test with fwcfg64 driver:
> 1. Do basic function test with fwcfg64 driver.
>    step1: Boot a guest with "-device=vmcoreinfo" option
>    step2: Install fwcfg64 driver in guest vm
steps 1 and 2 age good
>    step3: Trigger a BSOD through "nmi"

Do you need "nmi" here to get a proper dump file?
I was able to generated a valid Windbg dump file even
without this step. This is the most interesting and useful
scenario since it allows to generate dump file on a working
system for the future forensic data analysis.  

>    step4: Run "dump-guest-memory -w memory.dmp" in qemu monitor
>    step5: Check the memory.dmp can be open with windb tools
> 2. Do system reboot/ system shutdown test with fwcfg device.
> 3. Do fwcfg driver install/uninstall test.
> 4. Use signtool.exe to check whether the driver is digital signed 

All the rest is good.

Best regards,
Vadim.

> 
> Thanks a lot~
> Peixiu

(In reply to Vadim Rozenfeld from comment #6)
> (In reply to Peixiu Hou from comment #5)
> > (In reply to Vadim Rozenfeld from comment #4)
> > > (In reply to Vadim Rozenfeld from comment #3)
> > > > (In reply to Peixiu Hou from comment #2)
> > > > > Hi Meirav,
> > > > > 
> > > > > Thanks you file issue out, I have a few basic questions about this new
> > > > > feature:
> > > > > 
> > > > > 1) How can I connect the fwcfg64 device to a vm through qemu command line(I
> > > > > tried this command "-fw_cfg name=opt/com.name.domain.your.example,string=1",
> > > > > but booted up vm failed, it seems it's wrong)? 
> > > 
> > > Run VM with "-device=vmcoreinfo" option (currently only x64 version seems to
> > > be working 
> > > properly even thoug that x86 version is also included ito the build)
> > > 
> > > 
> > > > > 2) And in the vm, how to check the device's function?
> > > Inside of VM install fwcfgdmp.sys driver ( I use devcon for this) 
> > > After installation you should see QEMU FwCfg Device" under "System Devices"
> > > category in
> > > Device Manager Dialog.
> > > Next, from the qemu monitor run "dump-guest-memory -w memory.dmp". Upon
> > > completion this 
> > > command you should be able to open memory.dmp file with WinDbg as a normal
> > > crash dump file,
> > > generated during BSOD processing.
> > > 
> > 
> > Hi Vadim,
> > 
> > Thanks a lot for your answer, I tested on win10-64 and win2019 guest vm, the
> > device works well.
> > 
> > Used version:
> > RHEL9:
> > kernel-5.13.0-0.rc7.51.el9.x86_64
> > qemu-kvm-6.0.0-2.el9.x86_64
> > seabios-bin-1.14.0-4.el9.noarch
> > virtio-win-prewhql-202
> > 
> > RHEL8.5.0:
> > kernel-4.18.0-316.el8.x86_64
> > qemu-kvm-6.0.50-20.scrmod+el8.5.0+11566+2ca95551.wrb210623.x86_64
> > seabios-1.14.0-1.scrmod+el8.5.0+11566+2ca95551.x86_64
> > virtio-win-prewhql-202
> > 
> > And I also have some another questions want to confirm:
> > Q1: It seems this feature only support on windows guest? could you help to
> > confirm it? thanks~
> > 
> > Q2: Yes, I tried test on win8.1-32 guest, the fwcfg driver can be installed
> > successfully, but command dump-guest-memory hit error message as follows：
> >  (qemu) dump-guest-memory -w mem-8132.dmp
> 
> "-w" is for windows windbg 
> dump-guest-memory command should work for linux guests but it is out the
> scope of
> this bug.
> 
> >  Error: win-dump: invalid header, expected 'DU64', got 'DUMP'
> > If this feature will support on both windows x86_64 and windows i386 guest
> > os in the future? 
> > 
> That's true. 32-bit quests are not supported yet, and we need to clarify 
> if they need to be supported, because adding support for 32-bit quest will
> require some work from the quest driver side and may require some changes at 
> qemu side.
> 
> 
> > Q3: I plan follows tests for this feature, could you help to review it?
> > 1) Whql tests with "QEMU FwCfg Device".
> > 
> > 2) Function test with fwcfg64 driver:
> > 1. Do basic function test with fwcfg64 driver.
> >    step1: Boot a guest with "-device=vmcoreinfo" option
> >    step2: Install fwcfg64 driver in guest vm
> steps 1 and 2 age good
> >    step3: Trigger a BSOD through "nmi"
> 
> Do you need "nmi" here to get a proper dump file?
> I was able to generated a valid Windbg dump file even
> without this step. This is the most interesting and useful
> scenario since it allows to generate dump file on a working
> system for the future forensic data analysis.  
> 

I got it, I'll delete this step for the case, thank you for your analysis~ 

And I drafted RHEL8 - Fwcfg64_Test_Plan as attachment, could you help to review it? and any else do you want to add or modify?

Thanks a lot~
peixiu

> >    step4: Run "dump-guest-memory -w memory.dmp" in qemu monitor
> >    step5: Check the memory.dmp can be open with windb tools
> > 2. Do system reboot/ system shutdown test with fwcfg device.
> > 3. Do fwcfg driver install/uninstall test.
> > 4. Use signtool.exe to check whether the driver is digital signed 
> 
> All the rest is good.
> 
> Best regards,
> Vadim.
> 
> > 
> > Thanks a lot~
> > Peixiu

Passed whql test on Win11,Win2022,Win2019,Win2016,Win10-64,Win2012,Win2012-R2.

Set the bug to verified.Thanks