| Message ID | 20230722062115.11950-2-ajones@ventanamicro.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | kvm: Remove KVM_CREATE_IRQCHIP support assumption | expand |
On 22/07/2023 08.21, Andrew Jones wrote: > Since Linux commit 00f918f61c56 ("RISC-V: KVM: Skeletal in-kernel AIA > irqchip support") checking KVM_CAP_IRQCHIP returns non-zero when the > RISC-V platform has AIA. The cap indicates KVM supports at least one > of the following ioctls: > > KVM_CREATE_IRQCHIP > KVM_IRQ_LINE > KVM_GET_IRQCHIP > KVM_SET_IRQCHIP > KVM_GET_LAPIC > KVM_SET_LAPIC > > but the cap doesn't imply that KVM must support any of those ioctls > in particular. However, QEMU was assuming the KVM_CREATE_IRQCHIP > ioctl was supported. Stop making that assumption by introducing a > KVM parameter that each architecture which supports KVM_CREATE_IRQCHIP > sets. Adding parameters isn't awesome, but given how the > KVM_CAP_IRQCHIP isn't very helpful on its own, we don't have a lot of > options. > > Signed-off-by: Andrew Jones <ajones@ventanamicro.com> > --- > > While this fixes booting guests on riscv KVM with AIA it's unlikely > to get merged before the QEMU support for KVM AIA[1] lands, which > would also fix the issue. I think this patch is still worth considering > though since QEMU's assumption is wrong. > > [1] https://lore.kernel.org/all/20230714084429.22349-1-yongxuan.wang@sifive.com/ > > > accel/kvm/kvm-all.c | 5 ++++- > include/sysemu/kvm.h | 1 + > target/arm/kvm.c | 3 +++ > target/i386/kvm/kvm.c | 2 ++ > target/s390x/kvm/kvm.c | 3 +++ > 5 files changed, 13 insertions(+), 1 deletion(-) > > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c > index 373d876c0580..0f5ff8630502 100644 > --- a/accel/kvm/kvm-all.c > +++ b/accel/kvm/kvm-all.c > @@ -86,6 +86,7 @@ struct KVMParkedVcpu { > }; > > KVMState *kvm_state; > +bool kvm_has_create_irqchip; > bool kvm_kernel_irqchip; > bool kvm_split_irqchip; > bool kvm_async_interrupts_allowed; > @@ -2377,8 +2378,10 @@ static void kvm_irqchip_create(KVMState *s) > if (s->kernel_irqchip_split == ON_OFF_AUTO_ON) { > error_report("Split IRQ chip mode not supported."); > exit(1); > - } else { > + } else if (kvm_has_create_irqchip) { > ret = kvm_vm_ioctl(s, KVM_CREATE_IRQCHIP); > + } else { > + return; > } > } > if (ret < 0) { I think I'd do this differntly... at the beginning of the function, there is a check for kvm_check_extension(s, KVM_CAP_IRQCHIP) etc. ... I think you could now replace that check with a simple if (!kvm_has_create_irqchip) { return; } The "kvm_vm_enable_cap(s, KVM_CAP_S390_IRQCHIP, 0)" of course has to be moved to the target/s390x/kvm/kvm.c file, too. Thomas > diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h > index 115f0cca79d1..84b1bb3dc91e 100644 > --- a/include/sysemu/kvm.h > +++ b/include/sysemu/kvm.h > @@ -32,6 +32,7 @@ > #ifdef CONFIG_KVM_IS_POSSIBLE > > extern bool kvm_allowed; > +extern bool kvm_has_create_irqchip; > extern bool kvm_kernel_irqchip; > extern bool kvm_split_irqchip; > extern bool kvm_async_interrupts_allowed; > diff --git a/target/arm/kvm.c b/target/arm/kvm.c > index b4c7654f4980..2fa87b495d68 100644 > --- a/target/arm/kvm.c > +++ b/target/arm/kvm.c > @@ -250,6 +250,9 @@ int kvm_arm_get_max_vm_ipa_size(MachineState *ms, bool *fixed_ipa) > int kvm_arch_init(MachineState *ms, KVMState *s) > { > int ret = 0; > + > + kvm_has_create_irqchip = kvm_check_extension(s, KVM_CAP_IRQCHIP); > + > /* For ARM interrupt delivery is always asynchronous, > * whether we are using an in-kernel VGIC or not. > */ > diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c > index ebfaf3d24c79..6363e67f092d 100644 > --- a/target/i386/kvm/kvm.c > +++ b/target/i386/kvm/kvm.c > @@ -2771,6 +2771,8 @@ int kvm_arch_init(MachineState *ms, KVMState *s) > } > } > > + kvm_has_create_irqchip = kvm_check_extension(s, KVM_CAP_IRQCHIP); > + > return 0; > } > > diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c > index a9e5880349d9..c053304adf94 100644 > --- a/target/s390x/kvm/kvm.c > +++ b/target/s390x/kvm/kvm.c > @@ -391,6 +391,9 @@ int kvm_arch_init(MachineState *ms, KVMState *s) > } > > kvm_set_max_memslot_size(KVM_SLOT_MAX_BYTES); > + > + kvm_has_create_irqchip = kvm_check_extension(s, KVM_CAP_S390_IRQCHIP); > + > return 0; > } >
On Mon, Jul 24, 2023 at 11:53:39AM +0200, Thomas Huth wrote: > On 22/07/2023 08.21, Andrew Jones wrote: > > Since Linux commit 00f918f61c56 ("RISC-V: KVM: Skeletal in-kernel AIA > > irqchip support") checking KVM_CAP_IRQCHIP returns non-zero when the > > RISC-V platform has AIA. The cap indicates KVM supports at least one > > of the following ioctls: > > > > KVM_CREATE_IRQCHIP > > KVM_IRQ_LINE > > KVM_GET_IRQCHIP > > KVM_SET_IRQCHIP > > KVM_GET_LAPIC > > KVM_SET_LAPIC > > > > but the cap doesn't imply that KVM must support any of those ioctls > > in particular. However, QEMU was assuming the KVM_CREATE_IRQCHIP > > ioctl was supported. Stop making that assumption by introducing a > > KVM parameter that each architecture which supports KVM_CREATE_IRQCHIP > > sets. Adding parameters isn't awesome, but given how the > > KVM_CAP_IRQCHIP isn't very helpful on its own, we don't have a lot of > > options. > > > > Signed-off-by: Andrew Jones <ajones@ventanamicro.com> > > --- > > > > While this fixes booting guests on riscv KVM with AIA it's unlikely > > to get merged before the QEMU support for KVM AIA[1] lands, which > > would also fix the issue. I think this patch is still worth considering > > though since QEMU's assumption is wrong. > > > > [1] https://lore.kernel.org/all/20230714084429.22349-1-yongxuan.wang@sifive.com/ > > > > > > accel/kvm/kvm-all.c | 5 ++++- > > include/sysemu/kvm.h | 1 + > > target/arm/kvm.c | 3 +++ > > target/i386/kvm/kvm.c | 2 ++ > > target/s390x/kvm/kvm.c | 3 +++ > > 5 files changed, 13 insertions(+), 1 deletion(-) > > > > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c > > index 373d876c0580..0f5ff8630502 100644 > > --- a/accel/kvm/kvm-all.c > > +++ b/accel/kvm/kvm-all.c > > @@ -86,6 +86,7 @@ struct KVMParkedVcpu { > > }; > > KVMState *kvm_state; > > +bool kvm_has_create_irqchip; > > bool kvm_kernel_irqchip; > > bool kvm_split_irqchip; > > bool kvm_async_interrupts_allowed; > > @@ -2377,8 +2378,10 @@ static void kvm_irqchip_create(KVMState *s) > > if (s->kernel_irqchip_split == ON_OFF_AUTO_ON) { > > error_report("Split IRQ chip mode not supported."); > > exit(1); > > - } else { > > + } else if (kvm_has_create_irqchip) { > > ret = kvm_vm_ioctl(s, KVM_CREATE_IRQCHIP); > > + } else { > > + return; > > } > > } > > if (ret < 0) { > > I think I'd do this differntly... at the beginning of the function, there is > a check for kvm_check_extension(s, KVM_CAP_IRQCHIP) etc. ... I think you > could now replace that check with a simple > > if (!kvm_has_create_irqchip) { > return; > } > > The "kvm_vm_enable_cap(s, KVM_CAP_S390_IRQCHIP, 0)" of course has to be > moved to the target/s390x/kvm/kvm.c file, too. > Sounds good. I'll do that for v2. Thanks, drew
On Mon, Jul 24, 2023 at 11:53:39AM +0200, Thomas Huth wrote: > On 22/07/2023 08.21, Andrew Jones wrote: > > Since Linux commit 00f918f61c56 ("RISC-V: KVM: Skeletal in-kernel AIA > > irqchip support") checking KVM_CAP_IRQCHIP returns non-zero when the > > RISC-V platform has AIA. The cap indicates KVM supports at least one > > of the following ioctls: > > > > KVM_CREATE_IRQCHIP > > KVM_IRQ_LINE > > KVM_GET_IRQCHIP > > KVM_SET_IRQCHIP > > KVM_GET_LAPIC > > KVM_SET_LAPIC > > > > but the cap doesn't imply that KVM must support any of those ioctls > > in particular. However, QEMU was assuming the KVM_CREATE_IRQCHIP > > ioctl was supported. Stop making that assumption by introducing a > > KVM parameter that each architecture which supports KVM_CREATE_IRQCHIP > > sets. Adding parameters isn't awesome, but given how the > > KVM_CAP_IRQCHIP isn't very helpful on its own, we don't have a lot of > > options. > > > > Signed-off-by: Andrew Jones <ajones@ventanamicro.com> > > --- > > > > While this fixes booting guests on riscv KVM with AIA it's unlikely > > to get merged before the QEMU support for KVM AIA[1] lands, which > > would also fix the issue. I think this patch is still worth considering > > though since QEMU's assumption is wrong. > > > > [1] https://lore.kernel.org/all/20230714084429.22349-1-yongxuan.wang@sifive.com/ > > > > > > accel/kvm/kvm-all.c | 5 ++++- > > include/sysemu/kvm.h | 1 + > > target/arm/kvm.c | 3 +++ > > target/i386/kvm/kvm.c | 2 ++ > > target/s390x/kvm/kvm.c | 3 +++ > > 5 files changed, 13 insertions(+), 1 deletion(-) > > > > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c > > index 373d876c0580..0f5ff8630502 100644 > > --- a/accel/kvm/kvm-all.c > > +++ b/accel/kvm/kvm-all.c > > @@ -86,6 +86,7 @@ struct KVMParkedVcpu { > > }; > > KVMState *kvm_state; > > +bool kvm_has_create_irqchip; > > bool kvm_kernel_irqchip; > > bool kvm_split_irqchip; > > bool kvm_async_interrupts_allowed; > > @@ -2377,8 +2378,10 @@ static void kvm_irqchip_create(KVMState *s) > > if (s->kernel_irqchip_split == ON_OFF_AUTO_ON) { > > error_report("Split IRQ chip mode not supported."); > > exit(1); > > - } else { > > + } else if (kvm_has_create_irqchip) { > > ret = kvm_vm_ioctl(s, KVM_CREATE_IRQCHIP); > > + } else { > > + return; > > } > > } > > if (ret < 0) { > > I think I'd do this differntly... at the beginning of the function, there is > a check for kvm_check_extension(s, KVM_CAP_IRQCHIP) etc. ... I think you > could now replace that check with a simple > > if (!kvm_has_create_irqchip) { > return; > } > > The "kvm_vm_enable_cap(s, KVM_CAP_S390_IRQCHIP, 0)" of course has to be > moved to the target/s390x/kvm/kvm.c file, too. Actually, once we've moved the s390 cap enablement to the s390 file we can just drop the whole if-else chain. We don't want the if (!kvm_has_create_irqchip) at the top because we want to try kvm_arch_irqchip_create() even when kvm_has_create_irqchip is false, and we don't need to check KVM_CREATE_IRQCHIP for kvm_arch_irqchip_create() either. Keeping the check, as it is above in this v1, of kvm_has_create_irqchip for KVM_CREATE_IRQCHIP is still necessary, though. Thanks, drew
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 373d876c0580..0f5ff8630502 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -86,6 +86,7 @@ struct KVMParkedVcpu { }; KVMState *kvm_state; +bool kvm_has_create_irqchip; bool kvm_kernel_irqchip; bool kvm_split_irqchip; bool kvm_async_interrupts_allowed; @@ -2377,8 +2378,10 @@ static void kvm_irqchip_create(KVMState *s) if (s->kernel_irqchip_split == ON_OFF_AUTO_ON) { error_report("Split IRQ chip mode not supported."); exit(1); - } else { + } else if (kvm_has_create_irqchip) { ret = kvm_vm_ioctl(s, KVM_CREATE_IRQCHIP); + } else { + return; } } if (ret < 0) { diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h index 115f0cca79d1..84b1bb3dc91e 100644 --- a/include/sysemu/kvm.h +++ b/include/sysemu/kvm.h @@ -32,6 +32,7 @@ #ifdef CONFIG_KVM_IS_POSSIBLE extern bool kvm_allowed; +extern bool kvm_has_create_irqchip; extern bool kvm_kernel_irqchip; extern bool kvm_split_irqchip; extern bool kvm_async_interrupts_allowed; diff --git a/target/arm/kvm.c b/target/arm/kvm.c index b4c7654f4980..2fa87b495d68 100644 --- a/target/arm/kvm.c +++ b/target/arm/kvm.c @@ -250,6 +250,9 @@ int kvm_arm_get_max_vm_ipa_size(MachineState *ms, bool *fixed_ipa) int kvm_arch_init(MachineState *ms, KVMState *s) { int ret = 0; + + kvm_has_create_irqchip = kvm_check_extension(s, KVM_CAP_IRQCHIP); + /* For ARM interrupt delivery is always asynchronous, * whether we are using an in-kernel VGIC or not. */ diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index ebfaf3d24c79..6363e67f092d 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -2771,6 +2771,8 @@ int kvm_arch_init(MachineState *ms, KVMState *s) } } + kvm_has_create_irqchip = kvm_check_extension(s, KVM_CAP_IRQCHIP); + return 0; } diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c index a9e5880349d9..c053304adf94 100644 --- a/target/s390x/kvm/kvm.c +++ b/target/s390x/kvm/kvm.c @@ -391,6 +391,9 @@ int kvm_arch_init(MachineState *ms, KVMState *s) } kvm_set_max_memslot_size(KVM_SLOT_MAX_BYTES); + + kvm_has_create_irqchip = kvm_check_extension(s, KVM_CAP_S390_IRQCHIP); + return 0; }
Since Linux commit 00f918f61c56 ("RISC-V: KVM: Skeletal in-kernel AIA irqchip support") checking KVM_CAP_IRQCHIP returns non-zero when the RISC-V platform has AIA. The cap indicates KVM supports at least one of the following ioctls: KVM_CREATE_IRQCHIP KVM_IRQ_LINE KVM_GET_IRQCHIP KVM_SET_IRQCHIP KVM_GET_LAPIC KVM_SET_LAPIC but the cap doesn't imply that KVM must support any of those ioctls in particular. However, QEMU was assuming the KVM_CREATE_IRQCHIP ioctl was supported. Stop making that assumption by introducing a KVM parameter that each architecture which supports KVM_CREATE_IRQCHIP sets. Adding parameters isn't awesome, but given how the KVM_CAP_IRQCHIP isn't very helpful on its own, we don't have a lot of options. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> --- While this fixes booting guests on riscv KVM with AIA it's unlikely to get merged before the QEMU support for KVM AIA[1] lands, which would also fix the issue. I think this patch is still worth considering though since QEMU's assumption is wrong. [1] https://lore.kernel.org/all/20230714084429.22349-1-yongxuan.wang@sifive.com/ accel/kvm/kvm-all.c | 5 ++++- include/sysemu/kvm.h | 1 + target/arm/kvm.c | 3 +++ target/i386/kvm/kvm.c | 2 ++ target/s390x/kvm/kvm.c | 3 +++ 5 files changed, 13 insertions(+), 1 deletion(-)