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(-)
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) {
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;
}
--
2.41.0
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. 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
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
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