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pci-testdev: add optional memory bar

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Add memory bar to pci-testdev.  Size is configurable using the membar
property.  Setting the size to zero (default) turns it off.  Can be used
to check whether guests handle large pci bars correctly.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Gerd Hoffmann 2018-09-28 08:44:19 +02:00 • committed by Michael S. Tsirkin
parent 7115dcf4f1
commit 417463341e
2 changed files with 29 additions and 5 deletions
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15
docs/specs/pci-testdev.txt
View file

@ -1,11 +1,11 @@
pci-test is a device used for testing low level IO
device implements up to two BARs: BAR0 and BAR1.
Each BAR can be memory or IO. Guests must detect
BAR type and act accordingly.
device implements up to three BARs: BAR0, BAR1 and BAR2.
Each of BAR 0+1 can be memory or IO. Guests must detect
BAR types and act accordingly.
Each BAR size is up to 4K bytes.
Each BAR starts with the following header:
BAR 0+1 size is up to 4K bytes each.
BAR 0+1 starts with the following header:
typedef struct PCITestDevHdr {
uint8_t test; <- write-only, starts a given test number
@ -24,3 +24,8 @@ All registers are little endian.
device is expected to always implement tests 0 to N on each BAR, and to add new
tests with higher numbers. In this way a guest can scan test numbers until it
detects an access type that it does not support on this BAR, then stop.
BAR2 is a 64bit memory bar, without backing storage. It is disabled
by default and can be enabled using the membar=<size> property. This
can be used to test whether guests handle pci bars of a specific
(possibly quite large) size correctly.