On 05/07/15 19:01, Paolo Bonzini wrote: > > > On 07/05/2015 18:56, Jérémy Fanguède wrote: >> USB devices fail with a timeout error, as if the communication between >> the kernel and the devices fail at a certain point: >> usb 1-1: device not accepting address 5, error -110 >> usb usb1-port1: unable to enumerate USB device This is consistent with what I saw in my earlier testing. >> e1000 fails when the userspace tries to use it, with these type of >> kernel messages: >> e1000 0000:00:02.0 eth0: Detected Tx Unit Hang >> Tx Queue <0> >> TDH <d> >> TDT <d> >> next_to_use <d> >> next_to_clean <9> >> buffer_info[next_to_clean] >> time_stamp <ffff9311> >> next_to_watch <a> >> jiffies <ffff956a> >> next_to_watch.status <0> > > Can you find out what memory attributes the guest is using for the > memory---and if it's uncached, why? For USB, see "drivers/usb/core/hcd-pci.c", function usb_hcd_pci_probe(): it uses ioremap_nocache(). On the "why", that ioremap_nocache() call can be tracked to http://git.kernel.org/cgit/linux/kernel/git/tglx/history.git/commit/?id=a914dd8b (Feb 2002), which predates the kernel's move to git. I guess ioremap_nocache() is used simply because USB host controllers are supposed to programmed like that. And, from "arch/arm64/include/asm/io.h": #define ioremap_nocache(addr, size) __ioremap((addr), (size), __pgprot(PROT_DEVICE_nGnRE)) Thanks Laszlo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
