Hi On Mon, May 29, 2017 at 4:44 PM Igor Mammedov <imamm...@redhat.com> wrote:
> On Fri, 26 May 2017 13:59:09 +0000 > Marc-André Lureau <marcandre.lur...@gmail.com> wrote: > > > Hi > > > > On Thu, May 4, 2017 at 5:41 PM Igor Mammedov <imamm...@redhat.com> > wrote: > > > > > On Tue, 02 May 2017 19:03:15 +0000 > > > Marc-André Lureau <marcandre.lur...@gmail.com> wrote: > > > > > > > Hi > > > > > > > > On Tue, May 2, 2017 at 11:17 AM Igor Mammedov <imamm...@redhat.com> > > > wrote: > > > > > > > > > On Fri, 28 Apr 2017 14:28:38 +0000 > > > > > Marc-André Lureau <marcandre.lur...@gmail.com> wrote: > > > > > > > > > > > Hi > > > > > > > > > > > > On Fri, Apr 28, 2017 at 6:12 PM Ladi Prosek <lpro...@redhat.com> > > > wrote: > > > > > > > > > > > > > On Mon, Apr 24, 2017 at 3:03 PM, Marc-André Lureau > > > > > > > <marcandre.lur...@redhat.com> wrote: > > > > > > > > The VM coreinfo (vmcoreinfo) device is an emulated device > which > > > > > > > > exposes a 4k memory range to the guest to store various > > > informations > > > > > > > > useful to debug the guest OS. (it is greatly inspired by the > > > VMGENID > > > > > > > > device implementation) > > > > > > > > > > > > > > > > This is an early-boot alternative to the qemu-ga VMDUMP_INFO > > > event > > > > > > > > proposed in "[PATCH 00/21] WIP: dump: add kaslr support". > > > > > > > > > > > > > > > > If deemed more appropriate, we can consider writing to fw_cfg > > > > > directly > > > > > > > > instead of guest memory, now that qemu 2.9 supports it again. > > > > > > > > > > > > > > > > The proof-of-concept kernel module: > > > > > > > > > > > https://github.com/elmarco/vmgenid-test/blob/master/qemuvmci-test.c > > > > > > > > > > > > > > Here's a proof-of-concept Windows driver: > > > > > > > > > > > > > > > > > > > > > > > https://github.com/ladipro/kvm-guest-drivers-windows/tree/vmcoreinfo/vmcoreinfo > > > > > > > > > > > > > > I just wanted to be sure that it's possible to evaluate the > ADDR > > > > > > > method in Windows. > > > > > > > > > > > > > > From a practical point of view it is unfortunate that this > would > > > be a > > > > > > > completely new device. For Windows guests it means another > driver > > > > > > > binary and all the overhead associated with deploying it on > VMs. > > > Would > > > > > > > it be too crazy to add this functionality to the pvpanic > device? > > > The > > > > > > > mechanics could stay the same but it would be done under the > > > existing > > > > > > > ACPI\QEMU0001 device. > > > > > > > > > > > > > > > > > > > pvpanic is under _SB.PCI0.ISA, that could be problematic > > > > > > > > > > > > and _STA is a name field. > > > > > > > > > > > > Someone with more experience with ACPI could tell us if that make > > > sense > > > > > to > > > > > > merge both and how. > > > > > > > > > > > > Can't you handle 2 ACPI devices in the same windows driver > instead? > > > > > we use QEMU0001 to reserve IO ports for pvpanic device, > > > > > ASL wise there shouldn't problems with adding _ADDR method to it > > > > > > > > > > but then we probably should fold vmcoreinfo into pvpanic device > > > > > as well (QEMU and linux driver) > > > > > > > > > > > > > > pvpanic is x86-only afaict. > > > There is nothing that forces it to be x86 specific (beside being ISA > > > device), > > > ARM also can benefit from/use pvpanic if you make it pci device or just > > > plain > > > Device. > > > > > > > Could someone advise on a recommended solution here? > > > > Should we make a PCI variant of pvpanic and add the proposed vmcoreinfo > > ACPI/mem to it ? > > > > Tbh, I think I prefer to have seperate devices since they work > differently > > and vmcoreinfo doesn't require any bus device. > Considering pvpanic and vmcore are closely related, I'd prefer > it being one device. But I won't insist on it. > > Also instead of PCI device, I'd use plain Device as vmgenid does, > that would leave open question how to make legacy ISA based pvpanic > on top of it in case both are merged. > > Can we instead try to fit pvpanic functionality in the proposed vmcoreinfo device? This could be done in a future revision of the device. This way we don't have to deal with legacy ISA, and can make pvpanic functionality more portable. Tbh, I have no idea how to do the merging of the legacy ISA pvpanic with vmcoreinfo without breaking things, nor do I have the motivation to do so. More comments welcome (I would like to resend the patch as non-rfc this time, I hope we can make it in 2.10) Thanks -- Marc-André Lureau
