[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [RFC] ARM/ARM64: KVM: Implement KVM_FLUSH_DCACHE_GPA io
From: |
Laszlo Ersek |
Subject: |
Re: [Qemu-devel] [RFC] ARM/ARM64: KVM: Implement KVM_FLUSH_DCACHE_GPA ioctl |
Date: |
Fri, 15 May 2015 13:43:57 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 |
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
- [Qemu-devel] [RFC] ARM/ARM64: KVM: Implement KVM_FLUSH_DCACHE_GPA ioctl, Jérémy Fanguède, 2015/05/05
- Re: [Qemu-devel] [RFC] ARM/ARM64: KVM: Implement KVM_FLUSH_DCACHE_GPA ioctl, Christoffer Dall, 2015/05/06
- Re: [Qemu-devel] [RFC] ARM/ARM64: KVM: Implement KVM_FLUSH_DCACHE_GPA ioctl, Jérémy Fanguède, 2015/05/07
- Re: [Qemu-devel] [RFC] ARM/ARM64: KVM: Implement KVM_FLUSH_DCACHE_GPA ioctl, Christoffer Dall, 2015/05/07
- Re: [Qemu-devel] [RFC] ARM/ARM64: KVM: Implement KVM_FLUSH_DCACHE_GPA ioctl, Jérémy Fanguède, 2015/05/07
- Re: [Qemu-devel] [RFC] ARM/ARM64: KVM: Implement KVM_FLUSH_DCACHE_GPA ioctl, Christoffer Dall, 2015/05/07
- Re: [Qemu-devel] [RFC] ARM/ARM64: KVM: Implement KVM_FLUSH_DCACHE_GPA ioctl, Jérémy Fanguède, 2015/05/07
- Re: [Qemu-devel] [RFC] ARM/ARM64: KVM: Implement KVM_FLUSH_DCACHE_GPA ioctl, Paolo Bonzini, 2015/05/07
- Re: [Qemu-devel] [RFC] ARM/ARM64: KVM: Implement KVM_FLUSH_DCACHE_GPA ioctl,
Laszlo Ersek <=
- Re: [Qemu-devel] [RFC] ARM/ARM64: KVM: Implement KVM_FLUSH_DCACHE_GPA ioctl, Christoffer Dall, 2015/05/15
- Re: [Qemu-devel] [RFC] ARM/ARM64: KVM: Implement KVM_FLUSH_DCACHE_GPA ioctl, Paolo Bonzini, 2015/05/15