On 9/26/2012 4:01 PM, lejeczek wrote:
hi everybody
this is my first fiddling with passing through hardware
to a guest thus what follows may sound lame, apologies.
OS is rhel 6.3 64bit on a Dell poweredge box
two different VGAs, geforce 640 and radeon hd5450
Which one do you pass through?
guests are XP 32bit and 7 64bit
should be simple right?
XP seems to reports everything OK, I reckon sort of an
ultimate confirmation is that I get the guest on the
external screen
7 always! (regardless which VGA, different PCI slot also
tried, tried with different command line params) reports
the device marked with exclamation as non-running
I'm at loss for ideas of how to troubleshoot it further
Maybe the ATI or NVidia driver for the passed through
card accesses
additional registers in the Windows 7 version of those
drivers compared
to the XP version of those drivers.
My initial guess would be the PCI configuration space
registers, but it
could be any other registers or memory you forgot to pass
through.
Another possibility is that the passed through card has
"internal"
knowledge about the physical address of some of the
passed through
registers or memory, and the Windows 7 driver doesn't
like that the
simulated physical addresses where those are passed
through do not
match the physical reality reported by the card. If at
all possible, I
suggest that complex adapters (such as graphics card) are
passed through
with exactly the same "physical" addresses in the virtual
machine as in
the real physical machine.
Also, for extreme bus master PCI cards such as graphics
cards, it is
very important to use a CPU and/or chipset which
intercepts all
requests from the graphics hardware to the rest of the
computer (such
as DRAM and/or other cards) and lets qemu map those
exactly the same
way as those addresses are mapped for the CPU. For Intel
CPUs, this is
called VT-d, for most other brands (AMD, IBM 360) it is
called IOMMU.
help?
regards
Enjoy
Jakob