* [RFC PATCH v1 0/3] put arm64 kvm_config on a diet
@ 2020-08-04 12:44 Alex Bennée
2020-08-04 12:44 ` [PATCH v1 1/3] arm64: allow de-selection of ThunderX PCI controllers Alex Bennée
` (3 more replies)
0 siblings, 4 replies; 12+ messages in thread
From: Alex Bennée @ 2020-08-04 12:44 UTC (permalink / raw)
To: kvm, linux-arm-kernel
Cc: linux-kernel, kvmarm, christoffer.dall, maz, Alex Bennée
Hi,
When building guest kernels for virtualisation we were bringing in a
bunch of stuff from physical hardware which we don't need for our
idealised fixable virtual PCI devices. This series makes some Kconfig
changes to allow the ThunderX and XGene PCI drivers to be compiled
out. It also drops PCI_QUIRKS from the KVM guest build as a virtual
PCI device should be quirk free.
This is my first time hacking around Kconfig so I hope I've got the
balance between depends and selects right but please let be know if it
could be specified in a cleaner way.
Alex Bennée (3):
arm64: allow de-selection of ThunderX PCI controllers
arm64: gate the whole of pci-xgene on CONFIG_PCI_XGENE
kernel/configs: don't include PCI_QUIRKS in KVM guest configs
arch/arm64/Kconfig.platforms | 2 ++
arch/arm64/configs/defconfig | 1 +
drivers/pci/controller/Kconfig | 7 +++++++
drivers/pci/controller/Makefile | 8 +++-----
kernel/configs/kvm_guest.config | 1 +
5 files changed, 14 insertions(+), 5 deletions(-)
--
2.20.1
^ permalink raw reply [flat|nested] 12+ messages in thread* [PATCH v1 1/3] arm64: allow de-selection of ThunderX PCI controllers 2020-08-04 12:44 [RFC PATCH v1 0/3] put arm64 kvm_config on a diet Alex Bennée @ 2020-08-04 12:44 ` Alex Bennée 2020-08-17 17:11 ` Bjorn Helgaas 2020-08-04 12:44 ` [PATCH v1 2/3] arm64: gate the whole of pci-xgene on CONFIG_PCI_XGENE Alex Bennée ` (2 subsequent siblings) 3 siblings, 1 reply; 12+ messages in thread From: Alex Bennée @ 2020-08-04 12:44 UTC (permalink / raw) To: kvm, linux-arm-kernel Cc: linux-kernel, kvmarm, christoffer.dall, maz, Alex Bennée, Robert Richter, linux-pci For a pure VirtIO guest bringing in all the PCI quirk handling adds a significant amount of bloat to kernel we don't need. Solve this by adding a CONFIG symbol for the ThunderX PCI devices and allowing it to be turned off. Saving over 300k from the uncompressed vmlinux: -rwxr-xr-x 1 alex alex 85652472 Aug 3 16:48 vmlinux* -rwxr-xr-x 1 alex alex 86033880 Aug 3 16:39 vmlinux.orig* Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Cc: Robert Richter <rrichter@marvell.com> Cc: linux-pci@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org --- arch/arm64/Kconfig.platforms | 2 ++ arch/arm64/configs/defconfig | 1 + drivers/pci/controller/Kconfig | 7 +++++++ drivers/pci/controller/Makefile | 4 ++-- 4 files changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms index 8dd05b2a925c..a328eebdaa59 100644 --- a/arch/arm64/Kconfig.platforms +++ b/arch/arm64/Kconfig.platforms @@ -253,12 +253,14 @@ config ARCH_SPRD config ARCH_THUNDER bool "Cavium Inc. Thunder SoC Family" + select PCI_THUNDER help This enables support for Cavium's Thunder Family of SoCs. config ARCH_THUNDER2 bool "Cavium ThunderX2 Server Processors" select GPIOLIB + select PCI_THUNDER help This enables support for Cavium's ThunderX2 CN99XX family of server processors. diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig index 2ca7ba69c318..d840cba99941 100644 --- a/arch/arm64/configs/defconfig +++ b/arch/arm64/configs/defconfig @@ -199,6 +199,7 @@ CONFIG_PCI_HOST_GENERIC=y CONFIG_PCI_XGENE=y CONFIG_PCIE_ALTERA=y CONFIG_PCIE_ALTERA_MSI=y +CONFIG_PCI_THUNDER=y CONFIG_PCI_HOST_THUNDER_PEM=y CONFIG_PCI_HOST_THUNDER_ECAM=y CONFIG_PCIE_ROCKCHIP_HOST=m diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig index adddf21fa381..28335ffa5d48 100644 --- a/drivers/pci/controller/Kconfig +++ b/drivers/pci/controller/Kconfig @@ -286,6 +286,13 @@ config PCI_LOONGSON Say Y here if you want to enable PCI controller support on Loongson systems. +config PCI_THUNDER + bool "Thunder X PCIE controllers" + depends on ARM64 + select PCI_QUIRKS + help + Say Y here to enable ThunderX ECAM and PEM PCI controllers. + source "drivers/pci/controller/dwc/Kconfig" source "drivers/pci/controller/mobiveil/Kconfig" source "drivers/pci/controller/cadence/Kconfig" diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile index efd9733ead26..8fad4781a5d3 100644 --- a/drivers/pci/controller/Makefile +++ b/drivers/pci/controller/Makefile @@ -45,8 +45,8 @@ obj-y += mobiveil/ # ARM64 and use internal ifdefs to only build the pieces we need # depending on whether ACPI, the DT driver, or both are enabled. +obj-$(CONFIG_PCI_THUNDER) += pci-thunder-ecam.o +obj-$(CONFIG_PCI_THUNDER) += pci-thunder-pem.o ifdef CONFIG_PCI -obj-$(CONFIG_ARM64) += pci-thunder-ecam.o -obj-$(CONFIG_ARM64) += pci-thunder-pem.o obj-$(CONFIG_ARM64) += pci-xgene.o endif -- 2.20.1 ^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH v1 1/3] arm64: allow de-selection of ThunderX PCI controllers 2020-08-04 12:44 ` [PATCH v1 1/3] arm64: allow de-selection of ThunderX PCI controllers Alex Bennée @ 2020-08-17 17:11 ` Bjorn Helgaas 0 siblings, 0 replies; 12+ messages in thread From: Bjorn Helgaas @ 2020-08-17 17:11 UTC (permalink / raw) To: Alex Bennée Cc: kvm, linux-arm-kernel, linux-kernel, kvmarm, christoffer.dall, maz, Robert Richter, linux-pci On Tue, Aug 04, 2020 at 01:44:15PM +0100, Alex Bennée wrote: > For a pure VirtIO guest bringing in all the PCI quirk handling adds a > significant amount of bloat to kernel we don't need. Solve this by > adding a CONFIG symbol for the ThunderX PCI devices and allowing it to > be turned off. Saving over 300k from the uncompressed vmlinux: It *looks* like just turning off CONFIG_PCI_QUIRKS should be sufficient because pci-thunder-ecam.c and pci-thunder-pem.c are wrapped with: #if defined(CONFIG_PCI_HOST_THUNDER_PEM) || (defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS)) so if you turn off CONFIG_PCI_HOST_THUNDER_ECAM, CONFIG_PCI_HOST_THUNDER_PEM, and CONFIG_PCI_QUIRKS that should omit pci-thunder-ecam.o and pci-thunder-pem.o. But I must be missing something. > -rwxr-xr-x 1 alex alex 85652472 Aug 3 16:48 vmlinux* > -rwxr-xr-x 1 alex alex 86033880 Aug 3 16:39 vmlinux.orig* > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > Cc: Robert Richter <rrichter@marvell.com> > Cc: linux-pci@vger.kernel.org > Cc: linux-arm-kernel@lists.infradead.org > --- > arch/arm64/Kconfig.platforms | 2 ++ > arch/arm64/configs/defconfig | 1 + > drivers/pci/controller/Kconfig | 7 +++++++ > drivers/pci/controller/Makefile | 4 ++-- > 4 files changed, 12 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms > index 8dd05b2a925c..a328eebdaa59 100644 > --- a/arch/arm64/Kconfig.platforms > +++ b/arch/arm64/Kconfig.platforms > @@ -253,12 +253,14 @@ config ARCH_SPRD > > config ARCH_THUNDER > bool "Cavium Inc. Thunder SoC Family" > + select PCI_THUNDER > help > This enables support for Cavium's Thunder Family of SoCs. > > config ARCH_THUNDER2 > bool "Cavium ThunderX2 Server Processors" > select GPIOLIB > + select PCI_THUNDER Indent these with tabs, not spaces, to be consistent with other whitespace usage in this file. > help > This enables support for Cavium's ThunderX2 CN99XX family of > server processors. > diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig > index 2ca7ba69c318..d840cba99941 100644 > --- a/arch/arm64/configs/defconfig > +++ b/arch/arm64/configs/defconfig > @@ -199,6 +199,7 @@ CONFIG_PCI_HOST_GENERIC=y > CONFIG_PCI_XGENE=y > CONFIG_PCIE_ALTERA=y > CONFIG_PCIE_ALTERA_MSI=y > +CONFIG_PCI_THUNDER=y > CONFIG_PCI_HOST_THUNDER_PEM=y > CONFIG_PCI_HOST_THUNDER_ECAM=y > CONFIG_PCIE_ROCKCHIP_HOST=m > diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig > index adddf21fa381..28335ffa5d48 100644 > --- a/drivers/pci/controller/Kconfig > +++ b/drivers/pci/controller/Kconfig > @@ -286,6 +286,13 @@ config PCI_LOONGSON > Say Y here if you want to enable PCI controller support on > Loongson systems. > > +config PCI_THUNDER > + bool "Thunder X PCIE controllers" > + depends on ARM64 > + select PCI_QUIRKS > + help > + Say Y here to enable ThunderX ECAM and PEM PCI controllers. Indent with tabs, not spaces. The existing Kconfig help text refers to simply "Thunder", not "Thunder X", so both of these references should probably follow suit. s/PCIE controllers/PCIe controllers/ > source "drivers/pci/controller/dwc/Kconfig" > source "drivers/pci/controller/mobiveil/Kconfig" > source "drivers/pci/controller/cadence/Kconfig" > diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile > index efd9733ead26..8fad4781a5d3 100644 > --- a/drivers/pci/controller/Makefile > +++ b/drivers/pci/controller/Makefile > @@ -45,8 +45,8 @@ obj-y += mobiveil/ > # ARM64 and use internal ifdefs to only build the pieces we need > # depending on whether ACPI, the DT driver, or both are enabled. > > +obj-$(CONFIG_PCI_THUNDER) += pci-thunder-ecam.o > +obj-$(CONFIG_PCI_THUNDER) += pci-thunder-pem.o > ifdef CONFIG_PCI > -obj-$(CONFIG_ARM64) += pci-thunder-ecam.o > -obj-$(CONFIG_ARM64) += pci-thunder-pem.o > obj-$(CONFIG_ARM64) += pci-xgene.o > endif > -- > 2.20.1 > ^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH v1 2/3] arm64: gate the whole of pci-xgene on CONFIG_PCI_XGENE 2020-08-04 12:44 [RFC PATCH v1 0/3] put arm64 kvm_config on a diet Alex Bennée 2020-08-04 12:44 ` [PATCH v1 1/3] arm64: allow de-selection of ThunderX PCI controllers Alex Bennée @ 2020-08-04 12:44 ` Alex Bennée 2020-08-04 12:44 ` [PATCH v1 3/3] kernel/configs: don't include PCI_QUIRKS in KVM guest configs Alex Bennée 2020-08-04 13:18 ` [RFC PATCH v1 0/3] put arm64 kvm_config on a diet Ard Biesheuvel 3 siblings, 0 replies; 12+ messages in thread From: Alex Bennée @ 2020-08-04 12:44 UTC (permalink / raw) To: kvm, linux-arm-kernel Cc: linux-kernel, kvmarm, christoffer.dall, maz, Alex Bennée This is a little weirder as bits of the file are already conditioned on the exiting symbol. Either way they are not actually needed for non-xgene machines saving another 12k: -rwxr-xr-x 1 alex alex 86033880 Aug 3 16:39 vmlinux.orig* -rwxr-xr-x 1 alex alex 85652472 Aug 3 16:54 vmlinux.rm-thunder* -rwxr-xr-x 1 alex alex 85639808 Aug 3 17:12 vmlinux* Signed-off-by: Alex Bennée <alex.bennee@linaro.org> --- drivers/pci/controller/Makefile | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile index 8fad4781a5d3..3b9b72f5773a 100644 --- a/drivers/pci/controller/Makefile +++ b/drivers/pci/controller/Makefile @@ -47,6 +47,4 @@ obj-y += mobiveil/ obj-$(CONFIG_PCI_THUNDER) += pci-thunder-ecam.o obj-$(CONFIG_PCI_THUNDER) += pci-thunder-pem.o -ifdef CONFIG_PCI -obj-$(CONFIG_ARM64) += pci-xgene.o -endif +obj-$(CONFIG_PCI_XGENE) += pci-xgene.o -- 2.20.1 ^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH v1 3/3] kernel/configs: don't include PCI_QUIRKS in KVM guest configs 2020-08-04 12:44 [RFC PATCH v1 0/3] put arm64 kvm_config on a diet Alex Bennée 2020-08-04 12:44 ` [PATCH v1 1/3] arm64: allow de-selection of ThunderX PCI controllers Alex Bennée 2020-08-04 12:44 ` [PATCH v1 2/3] arm64: gate the whole of pci-xgene on CONFIG_PCI_XGENE Alex Bennée @ 2020-08-04 12:44 ` Alex Bennée 2020-08-04 13:46 ` Marc Zyngier 2020-08-04 13:18 ` [RFC PATCH v1 0/3] put arm64 kvm_config on a diet Ard Biesheuvel 3 siblings, 1 reply; 12+ messages in thread From: Alex Bennée @ 2020-08-04 12:44 UTC (permalink / raw) To: kvm, linux-arm-kernel Cc: linux-kernel, kvmarm, christoffer.dall, maz, Alex Bennée The VIRTIO_PCI support is an idealised PCI bus, we don't need a bunch of bloat for real world hardware for a VirtIO guest. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> --- kernel/configs/kvm_guest.config | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/configs/kvm_guest.config b/kernel/configs/kvm_guest.config index 208481d91090..672863a2fdf1 100644 --- a/kernel/configs/kvm_guest.config +++ b/kernel/configs/kvm_guest.config @@ -13,6 +13,7 @@ CONFIG_IP_PNP_DHCP=y CONFIG_BINFMT_ELF=y CONFIG_PCI=y CONFIG_PCI_MSI=y +CONFIG_PCI_QUIRKS=n CONFIG_DEBUG_KERNEL=y CONFIG_VIRTUALIZATION=y CONFIG_HYPERVISOR_GUEST=y -- 2.20.1 ^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH v1 3/3] kernel/configs: don't include PCI_QUIRKS in KVM guest configs 2020-08-04 12:44 ` [PATCH v1 3/3] kernel/configs: don't include PCI_QUIRKS in KVM guest configs Alex Bennée @ 2020-08-04 13:46 ` Marc Zyngier 2020-08-04 14:44 ` Alex Bennée 0 siblings, 1 reply; 12+ messages in thread From: Marc Zyngier @ 2020-08-04 13:46 UTC (permalink / raw) To: Alex Bennée Cc: kvm, linux-arm-kernel, linux-kernel, kvmarm, christoffer.dall On 2020-08-04 13:44, Alex Bennée wrote: > The VIRTIO_PCI support is an idealised PCI bus, we don't need a bunch > of bloat for real world hardware for a VirtIO guest. Who says this guest will only have virtio devices? Or even, virtio devices without bugs? Given that said device can come from any VMM, I'm not sure this is the right thing to do. Thanks, M. > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > --- > kernel/configs/kvm_guest.config | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/configs/kvm_guest.config > b/kernel/configs/kvm_guest.config > index 208481d91090..672863a2fdf1 100644 > --- a/kernel/configs/kvm_guest.config > +++ b/kernel/configs/kvm_guest.config > @@ -13,6 +13,7 @@ CONFIG_IP_PNP_DHCP=y > CONFIG_BINFMT_ELF=y > CONFIG_PCI=y > CONFIG_PCI_MSI=y > +CONFIG_PCI_QUIRKS=n > CONFIG_DEBUG_KERNEL=y > CONFIG_VIRTUALIZATION=y > CONFIG_HYPERVISOR_GUEST=y -- Jazz is not dead. It just smells funny... ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v1 3/3] kernel/configs: don't include PCI_QUIRKS in KVM guest configs 2020-08-04 13:46 ` Marc Zyngier @ 2020-08-04 14:44 ` Alex Bennée 2020-08-04 14:59 ` Marc Zyngier 0 siblings, 1 reply; 12+ messages in thread From: Alex Bennée @ 2020-08-04 14:44 UTC (permalink / raw) To: Marc Zyngier Cc: kvm, linux-arm-kernel, linux-kernel, kvmarm, christoffer.dall Marc Zyngier <maz@kernel.org> writes: > On 2020-08-04 13:44, Alex Bennée wrote: >> The VIRTIO_PCI support is an idealised PCI bus, we don't need a bunch >> of bloat for real world hardware for a VirtIO guest. > > Who says this guest will only have virtio devices? This is true - although what is the point of kvm_guest.config? We certainly turn on a whole bunch of virt optimised pathways with PARAVIRT and HYPERVISOR_GUEST along with the rest of VirtIO. > Or even, virtio devices without bugs? Given that said device can > come from any VMM, I'm not sure this is the right thing to do. Perhaps this patch is one too far. I don't mind dropping it as long as I can still slim down the kernels I know don't need the extra bloat. > > Thanks, > > M. > >> >> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> >> --- >> kernel/configs/kvm_guest.config | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/kernel/configs/kvm_guest.config >> b/kernel/configs/kvm_guest.config >> index 208481d91090..672863a2fdf1 100644 >> --- a/kernel/configs/kvm_guest.config >> +++ b/kernel/configs/kvm_guest.config >> @@ -13,6 +13,7 @@ CONFIG_IP_PNP_DHCP=y >> CONFIG_BINFMT_ELF=y >> CONFIG_PCI=y >> CONFIG_PCI_MSI=y >> +CONFIG_PCI_QUIRKS=n >> CONFIG_DEBUG_KERNEL=y >> CONFIG_VIRTUALIZATION=y >> CONFIG_HYPERVISOR_GUEST=y -- Alex Bennée ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v1 3/3] kernel/configs: don't include PCI_QUIRKS in KVM guest configs 2020-08-04 14:44 ` Alex Bennée @ 2020-08-04 14:59 ` Marc Zyngier 2020-08-04 15:40 ` Alex Bennée 0 siblings, 1 reply; 12+ messages in thread From: Marc Zyngier @ 2020-08-04 14:59 UTC (permalink / raw) To: Alex Bennée Cc: kvm, linux-arm-kernel, linux-kernel, kvmarm, christoffer.dall On 2020-08-04 15:44, Alex Bennée wrote: > Marc Zyngier <maz@kernel.org> writes: > >> On 2020-08-04 13:44, Alex Bennée wrote: >>> The VIRTIO_PCI support is an idealised PCI bus, we don't need a bunch >>> of bloat for real world hardware for a VirtIO guest. >> >> Who says this guest will only have virtio devices? > > This is true - although what is the point of kvm_guest.config? We > certainly turn on a whole bunch of virt optimised pathways with > PARAVIRT > and HYPERVISOR_GUEST along with the rest of VirtIO. Most of which actually qualifies as bloat itself as far as KVM/arm64 is concerned... M. -- Jazz is not dead. It just smells funny... ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v1 3/3] kernel/configs: don't include PCI_QUIRKS in KVM guest configs 2020-08-04 14:59 ` Marc Zyngier @ 2020-08-04 15:40 ` Alex Bennée 2020-08-04 17:16 ` Marc Zyngier 0 siblings, 1 reply; 12+ messages in thread From: Alex Bennée @ 2020-08-04 15:40 UTC (permalink / raw) To: Marc Zyngier Cc: kvm, linux-arm-kernel, linux-kernel, kvmarm, christoffer.dall Marc Zyngier <maz@kernel.org> writes: > On 2020-08-04 15:44, Alex Bennée wrote: >> Marc Zyngier <maz@kernel.org> writes: >> >>> On 2020-08-04 13:44, Alex Bennée wrote: >>>> The VIRTIO_PCI support is an idealised PCI bus, we don't need a bunch >>>> of bloat for real world hardware for a VirtIO guest. >>> >>> Who says this guest will only have virtio devices? >> >> This is true - although what is the point of kvm_guest.config? We >> certainly turn on a whole bunch of virt optimised pathways with >> PARAVIRT >> and HYPERVISOR_GUEST along with the rest of VirtIO. > > Most of which actually qualifies as bloat itself as far as KVM/arm64 > is concerned... So here is the question - does the kernel care about having a blessed config for a minimal viable guest? They are certainly used in the cloud but I understand the kernel is trying to get away from having a zoo of configs. What is the actual point of kvm_guest.config? Just an easy enabling for developers? > > M. -- Alex Bennée ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v1 3/3] kernel/configs: don't include PCI_QUIRKS in KVM guest configs 2020-08-04 15:40 ` Alex Bennée @ 2020-08-04 17:16 ` Marc Zyngier 0 siblings, 0 replies; 12+ messages in thread From: Marc Zyngier @ 2020-08-04 17:16 UTC (permalink / raw) To: Alex Bennée Cc: kvm, linux-arm-kernel, linux-kernel, kvmarm, christoffer.dall On 2020-08-04 16:40, Alex Bennée wrote: > Marc Zyngier <maz@kernel.org> writes: > >> On 2020-08-04 15:44, Alex Bennée wrote: >>> Marc Zyngier <maz@kernel.org> writes: >>> >>>> On 2020-08-04 13:44, Alex Bennée wrote: >>>>> The VIRTIO_PCI support is an idealised PCI bus, we don't need a >>>>> bunch >>>>> of bloat for real world hardware for a VirtIO guest. >>>> >>>> Who says this guest will only have virtio devices? >>> >>> This is true - although what is the point of kvm_guest.config? We >>> certainly turn on a whole bunch of virt optimised pathways with >>> PARAVIRT >>> and HYPERVISOR_GUEST along with the rest of VirtIO. >> >> Most of which actually qualifies as bloat itself as far as KVM/arm64 >> is concerned... > > So here is the question - does the kernel care about having a blessed > config for a minimal viable guest? They are certainly used in the cloud > but I understand the kernel is trying to get away from having a zoo of > configs. What is the actual point of kvm_guest.config? Just an easy > enabling for developers? The cloud vendor I know certainly doesn't provide a "dumbed down" kernel configuration. What they run is either a distro kernel or something that fits their environment (which does include HW PCI devices, and hardly any virtio device). My take is that this kvm-special config isn't that useful in the real world, and I don't believe there is such thing as a "minimal viable guest" config, certainly not across architectures and VMMs. Hopefully it fits someone's development workflow, but that's probably it. M. -- Jazz is not dead. It just smells funny... ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [RFC PATCH v1 0/3] put arm64 kvm_config on a diet 2020-08-04 12:44 [RFC PATCH v1 0/3] put arm64 kvm_config on a diet Alex Bennée ` (2 preceding siblings ...) 2020-08-04 12:44 ` [PATCH v1 3/3] kernel/configs: don't include PCI_QUIRKS in KVM guest configs Alex Bennée @ 2020-08-04 13:18 ` Ard Biesheuvel 2020-08-04 14:47 ` Alex Bennée 3 siblings, 1 reply; 12+ messages in thread From: Ard Biesheuvel @ 2020-08-04 13:18 UTC (permalink / raw) To: Alex Bennée Cc: kvm, Linux ARM, Marc Zyngier, Christoffer Dall, Linux Kernel Mailing List, kvmarm On Tue, 4 Aug 2020 at 14:45, Alex Bennée <alex.bennee@linaro.org> wrote: > > Hi, > > When building guest kernels for virtualisation we were bringing in a > bunch of stuff from physical hardware which we don't need for our > idealised fixable virtual PCI devices. This series makes some Kconfig > changes to allow the ThunderX and XGene PCI drivers to be compiled > out. It also drops PCI_QUIRKS from the KVM guest build as a virtual > PCI device should be quirk free. > What about PCI passthrough? > This is my first time hacking around Kconfig so I hope I've got the > balance between depends and selects right but please let be know if it > could be specified in a cleaner way. > > Alex Bennée (3): > arm64: allow de-selection of ThunderX PCI controllers > arm64: gate the whole of pci-xgene on CONFIG_PCI_XGENE > kernel/configs: don't include PCI_QUIRKS in KVM guest configs > > arch/arm64/Kconfig.platforms | 2 ++ > arch/arm64/configs/defconfig | 1 + > drivers/pci/controller/Kconfig | 7 +++++++ > drivers/pci/controller/Makefile | 8 +++----- > kernel/configs/kvm_guest.config | 1 + > 5 files changed, 14 insertions(+), 5 deletions(-) > > -- > 2.20.1 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [RFC PATCH v1 0/3] put arm64 kvm_config on a diet 2020-08-04 13:18 ` [RFC PATCH v1 0/3] put arm64 kvm_config on a diet Ard Biesheuvel @ 2020-08-04 14:47 ` Alex Bennée 0 siblings, 0 replies; 12+ messages in thread From: Alex Bennée @ 2020-08-04 14:47 UTC (permalink / raw) To: Ard Biesheuvel Cc: kvm, Linux ARM, Marc Zyngier, Christoffer Dall, Linux Kernel Mailing List, kvmarm Ard Biesheuvel <ardb@kernel.org> writes: > On Tue, 4 Aug 2020 at 14:45, Alex Bennée <alex.bennee@linaro.org> wrote: >> >> Hi, >> >> When building guest kernels for virtualisation we were bringing in a >> bunch of stuff from physical hardware which we don't need for our >> idealised fixable virtual PCI devices. This series makes some Kconfig >> changes to allow the ThunderX and XGene PCI drivers to be compiled >> out. It also drops PCI_QUIRKS from the KVM guest build as a virtual >> PCI device should be quirk free. >> > > What about PCI passthrough? That is a good point - how much of the host PCI controller is visible to a pass-through guest? AIUI in passthrough the driver only interacts with the particular cards IO window. How many quirks are visible just at the device level (rather than the bus itself)? That said I think the last patch might get dropped as long as the user has the option to slim down their kernel with the first two. > >> This is my first time hacking around Kconfig so I hope I've got the >> balance between depends and selects right but please let be know if it >> could be specified in a cleaner way. >> >> Alex Bennée (3): >> arm64: allow de-selection of ThunderX PCI controllers >> arm64: gate the whole of pci-xgene on CONFIG_PCI_XGENE >> kernel/configs: don't include PCI_QUIRKS in KVM guest configs >> >> arch/arm64/Kconfig.platforms | 2 ++ >> arch/arm64/configs/defconfig | 1 + >> drivers/pci/controller/Kconfig | 7 +++++++ >> drivers/pci/controller/Makefile | 8 +++----- >> kernel/configs/kvm_guest.config | 1 + >> 5 files changed, 14 insertions(+), 5 deletions(-) >> >> -- >> 2.20.1 >> >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- Alex Bennée ^ permalink raw reply [flat|nested] 12+ messages in thread
end of thread, other threads:[~2020-08-17 17:24 UTC | newest] Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-08-04 12:44 [RFC PATCH v1 0/3] put arm64 kvm_config on a diet Alex Bennée 2020-08-04 12:44 ` [PATCH v1 1/3] arm64: allow de-selection of ThunderX PCI controllers Alex Bennée 2020-08-17 17:11 ` Bjorn Helgaas 2020-08-04 12:44 ` [PATCH v1 2/3] arm64: gate the whole of pci-xgene on CONFIG_PCI_XGENE Alex Bennée 2020-08-04 12:44 ` [PATCH v1 3/3] kernel/configs: don't include PCI_QUIRKS in KVM guest configs Alex Bennée 2020-08-04 13:46 ` Marc Zyngier 2020-08-04 14:44 ` Alex Bennée 2020-08-04 14:59 ` Marc Zyngier 2020-08-04 15:40 ` Alex Bennée 2020-08-04 17:16 ` Marc Zyngier 2020-08-04 13:18 ` [RFC PATCH v1 0/3] put arm64 kvm_config on a diet Ard Biesheuvel 2020-08-04 14:47 ` Alex Bennée
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