RE: [PATCH v2 0/3] KVM: arm/arm64: Allow to use KVM without in-kernel irqchip
Hello! > Believe it or not, we're not only patch reviewing machines, and if you > count the number of pending patches, you'll quickly notice that yours > are basically noise in the grand scheme of things. > > So please cut us some slack. What do you mean exactly? Stop discussions and just do everything you suggest before respin? Plz don't attempt to read this between lines, i can be bad at communication; this is not a complain and/or hurt indication, i am just asking. :) > > complete implementation of API which allows to emulate GIC in userspace by > > qemu, and now i can run any virtual machine, including generic timer, on > > vGIC-less machine. RasPI-2 is expected to benefit too. > > Do you mean feeding interrupts back to userspace? Yes, exactly. I have a working proof-of-concept here. > How is that going to > work with the active-timer series that really mandates a full blown GIC? > Your pet platform might cope with it, but I can't see that happening on > the RPi. I don't know, sorry, things are happening too fast and i can't follow everything. Well, actually it is possible to work without virtual timer at all. Yes, this means qemu has to implement some memory-mapped timer. With HW models like vexpress this is already done and works fine. I even tried to address this: https://lists.gnu.org/archive/html/qemu-devel/2015-06/msg06627.html, but Peter suggested to complete an API instead. I have done this as a proof-of-concept and case study for my project, so i want to upstream this in order not to be lost. After all, recent specs say that generic timer can also be memory-mapped. So, making KVM working without both vGIC and vTimer is not a real problem. This patchset addresses this scenario too, just needs some extra bits on vtimer side (ability to init KVM without it). Kind regards, Pavel Fedin Expert Engineer Samsung Electronics Research center Russia -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [PATCH v2 1/3] KVM: arm: Fix NULL pointer dereference if KVM is used without in-kernel irqchip
Hello! > I'd appreciate a better commit log. Which patch broke it, why is that > necessary. It was broken by 662d9715840aef44dcb573b0f9fab9e8319c868a. Actually, runtime detection was never implemented. The patch message just says that it can be done. And in order to run KVM on my lame board i had to disable VGIC and VTIMER in kernel .config. The actual breakage happened because without these definitions kvm_vgic_map_resources() was just a do-nothing inline. vGIC can perfectly be emulated by userspace. And even generic timer can, with some tricks. So i decided to restore this functionality. Kind regards, Pavel Fedin Expert Engineer Samsung Electronics Research center Russia -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH] vfio: Enable VFIO device for powerpc
ec53500f "kvm: Add VFIO device" added a special KVM pseudo-device which is used to handle any necessary interactions between KVM and VFIO. Currently that device is built on x86 and ARM, but not powerpc, although powerpc does support both KVM and VFIO. This makes things awkward in userspace Currently qemu prints an alarming error message if you attempt to use VFIO and it can't initialize the KVM VFIO device. We don't want to remove the warning, because lack of the KVM VFIO device could mean coherency problems on x86. On powerpc, however, the error is harmless but looks disturbing, and a test based on host architecture in qemu would be ugly, and break if we do need the KVM VFIO device for something important in future. There's nothing preventing the KVM VFIO device from being built for powerpc, so this patch turns it on. It won't actually do anything, since we don't define any of the arch_*() hooks, but it will make qemu happy and we can extend it in future if we need to. Signed-off-by: David Gibson --- arch/powerpc/kvm/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/kvm/Makefile b/arch/powerpc/kvm/Makefile index 0570eef..7f7b6d8 100644 --- a/arch/powerpc/kvm/Makefile +++ b/arch/powerpc/kvm/Makefile @@ -8,7 +8,7 @@ ccflags-y := -Ivirt/kvm -Iarch/powerpc/kvm KVM := ../../../virt/kvm common-objs-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o \ - $(KVM)/eventfd.o + $(KVM)/eventfd.o $(KVM)/vfio.o CFLAGS_e500_mmu.o := -I. CFLAGS_e500_mmu_host.o := -I. -- 2.4.3 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
