Hi Drew, On 6/21/19 6:34 PM, Andrew Jones wrote: > kvm_arm_create_scratch_host_vcpu() takes a struct kvm_vcpu_init > parameter. Rather than just using it as an output parameter to > pass back the preferred target, use it also as an input parameter, > allowing a caller to pass a selected target if they wish and to > also pass cpu features. If the caller doesn't want to select a > target they can pass -1 for the target which indicates they want > to use the preferred target and have it passed back like before. > > Signed-off-by: Andrew Jones <drjo...@redhat.com> > --- > target/arm/kvm.c | 20 +++++++++++++++----- > target/arm/kvm32.c | 6 +++++- > target/arm/kvm64.c | 6 +++++- > 3 files changed, 25 insertions(+), 7 deletions(-) > > diff --git a/target/arm/kvm.c b/target/arm/kvm.c > index 60645a196d3d..66c0c198604a 100644 > --- a/target/arm/kvm.c > +++ b/target/arm/kvm.c > @@ -64,7 +64,7 @@ bool kvm_arm_create_scratch_host_vcpu(const uint32_t > *cpus_to_try, > int *fdarray, > struct kvm_vcpu_init *init) > { > - int ret, kvmfd = -1, vmfd = -1, cpufd = -1; > + int ret = 0, kvmfd = -1, vmfd = -1, cpufd = -1; > > kvmfd = qemu_open("/dev/kvm", O_RDWR); > if (kvmfd < 0) { > @@ -84,7 +84,14 @@ bool kvm_arm_create_scratch_host_vcpu(const uint32_t > *cpus_to_try, > goto finish; > } > > - ret = ioctl(vmfd, KVM_ARM_PREFERRED_TARGET, init); > + if (init->target == -1) { > + struct kvm_vcpu_init preferred; > + > + ret = ioctl(vmfd, KVM_ARM_PREFERRED_TARGET, &preferred); > + if (!ret) { > + init->target = preferred.target; wouldn't it be safe to copy the whole struct. Kernel code says: /* * For now, we don't return any features. * In future, we might use features to return target * specific features available for the preferred * target type. */
> + } > + } > if (ret >= 0) { > ret = ioctl(cpufd, KVM_ARM_VCPU_INIT, init); > if (ret < 0) { > @@ -96,10 +103,12 @@ bool kvm_arm_create_scratch_host_vcpu(const uint32_t > *cpus_to_try, > * creating one kind of guest CPU which is its preferred > * CPU type. > */ > + struct kvm_vcpu_init try; > + > while (*cpus_to_try != QEMU_KVM_ARM_TARGET_NONE) { > - init->target = *cpus_to_try++; > - memset(init->features, 0, sizeof(init->features)); > - ret = ioctl(cpufd, KVM_ARM_VCPU_INIT, init); > + try.target = *cpus_to_try++; > + memcpy(try.features, init->features, sizeof(init->features)); > + ret = ioctl(cpufd, KVM_ARM_VCPU_INIT, &try); > if (ret >= 0) { > break; > } > @@ -107,6 +116,7 @@ bool kvm_arm_create_scratch_host_vcpu(const uint32_t > *cpus_to_try, > if (ret < 0) { > goto err; > } > + init->target = try.target; > } else { > /* Treat a NULL cpus_to_try argument the same as an empty > * list, which means we will fail the call since this must > diff --git a/target/arm/kvm32.c b/target/arm/kvm32.c > index 51f78f722b18..d007f6bd34d7 100644 > --- a/target/arm/kvm32.c > +++ b/target/arm/kvm32.c > @@ -54,7 +54,11 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures > *ahcf) > QEMU_KVM_ARM_TARGET_CORTEX_A15, > QEMU_KVM_ARM_TARGET_NONE > }; > - struct kvm_vcpu_init init; > + /* > + * target = -1 informs kvm_arm_create_scratch_host_vcpu() > + * to use the preferred target > + */ > + struct kvm_vcpu_init init = { .target = -1, }; > > if (!kvm_arm_create_scratch_host_vcpu(cpus_to_try, fdarray, &init)) { > return false; > diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c > index 9fc7f078cf68..2821135a4d0e 100644 > --- a/target/arm/kvm64.c > +++ b/target/arm/kvm64.c > @@ -502,7 +502,11 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures > *ahcf) > KVM_ARM_TARGET_CORTEX_A57, > QEMU_KVM_ARM_TARGET_NONE > }; > - struct kvm_vcpu_init init; > + /* > + * target = -1 informs kvm_arm_create_scratch_host_vcpu() > + * to use the preferred target > + */ > + struct kvm_vcpu_init init = { .target = -1, }; > > if (!kvm_arm_create_scratch_host_vcpu(cpus_to_try, fdarray, &init)) { > return false; > Besides Reviewed-by: Eric Auger <eric.au...@redhat.com> Thanks Eric