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;
}
--
2.41.0On 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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