Page 2 of 2
Re: Read from usb storage device
Posted: Sat Jun 03, 2017 11:16 am
by SpyderTL
I added a ticket on their support site. I may go digging around in their source code if I get some time. This will probably have to be done in the guest BIOS, though.
https://www.virtualbox.org/ticket/16809
Re: Read from usb storage device
Posted: Wed Jun 14, 2017 3:01 pm
by SpyderTL
Good news!
The VirtualBox bug guy has decided that this isn't a bug...
He "suggests" that you just don't use PCI Express in VirtualBox.
At least he could have lied and said that they will look into it.
Re: Read from usb storage device
Posted: Wed Jun 14, 2017 4:36 pm
by Brendan
Hi,
SpyderTL wrote:Good news!
The VirtualBox bug guy has decided that this isn't a bug...
That guy is a fool.
The PCI Firmware Specification does say "
If the operating system does not natively comprehend reserving the MMCFG region, the MMCFG region must be reserved by firmware."; but (excluding "OS and hardware as single product" scenarios that don't apply to VirtualBox) firmware has no way to know if the OS that the end user might decide to install does or doesn't natively comprehend reserving the MMCFG region, and therefore firmware needs to make "safe assumptions" (and assume that the MMCFG region must be reserved by firmware).
SpyderTL wrote:He "suggests" that you just don't use PCI Express in VirtualBox.
Exactly - it breaks backward compatibility for the sake of avoiding spending 5 minutes on a trivial change.
For my case, it doesn't really matter too much - it just means that anyone using VirtualBox wins a free warning in the OS's event log.
Cheers,
Brendan
Re: Read from usb storage device
Posted: Wed Jun 14, 2017 4:50 pm
by LtG
SpyderTL wrote:Good news!
The VirtualBox bug guy has decided that this isn't a bug...
He "suggests" that you just don't use PCI Express in VirtualBox.
At least he could have lied and said that they will look into it.
Given that E820 is PC specific and PCI is not PC specific, the PCI spec obviously can't say that E820 _MUST_ do anything, since E820 might not even exist. Even newer PC's might not have E820 if hey only support UEFI and don't support legacy BIOS.
Further, the PCI spec doesn't really have a say when it comes to other "standards", except for giving recommendations. If the memory map doesn't include everything then it's invalid. The firmware must include reserved areas in the memory map(s) as well.