Hi, On Wed, Mar 02, 2022 at 02:07:35PM +0000, Sebastian Ene wrote: > This patch adds support for stolen time by sharing a memory region > with the guest which will be used by the hypervisor to store the stolen > time information. Reserve a 64kb MMIO memory region after the RTC peripheral > to be used by pvtime. The exact format of the structure stored by the > hypervisor is described in the ARM DEN0057A document. > > Signed-off-by: Sebastian Ene <sebastianene@xxxxxxxxxx> > --- > Makefile | 1 + > arm/aarch64/arm-cpu.c | 2 +- > arm/aarch64/include/kvm/kvm-cpu-arch.h | 1 + > arm/aarch64/pvtime.c | 103 +++++++++++++++++++++++++ > arm/include/arm-common/kvm-arch.h | 6 +- > include/kvm/kvm-config.h | 1 + > 6 files changed, 112 insertions(+), 2 deletions(-) > create mode 100644 arm/aarch64/pvtime.c > > diff --git a/Makefile b/Makefile > index f251147..e9121dc 100644 > --- a/Makefile > +++ b/Makefile > @@ -182,6 +182,7 @@ ifeq ($(ARCH), arm64) > OBJS += arm/aarch64/arm-cpu.o > OBJS += arm/aarch64/kvm-cpu.o > OBJS += arm/aarch64/kvm.o > + OBJS += arm/aarch64/pvtime.o > ARCH_INCLUDE := $(HDRS_ARM_COMMON) > ARCH_INCLUDE += -Iarm/aarch64/include > > diff --git a/arm/aarch64/arm-cpu.c b/arm/aarch64/arm-cpu.c > index d7572b7..7e4a3c1 100644 > --- a/arm/aarch64/arm-cpu.c > +++ b/arm/aarch64/arm-cpu.c > @@ -22,7 +22,7 @@ static void generate_fdt_nodes(void *fdt, struct kvm *kvm) > static int arm_cpu__vcpu_init(struct kvm_cpu *vcpu) > { > vcpu->generate_fdt_nodes = generate_fdt_nodes; > - return 0; > + return kvm_cpu__setup_pvtime(vcpu); > } > > static struct kvm_arm_target target_generic_v8 = { > diff --git a/arm/aarch64/include/kvm/kvm-cpu-arch.h b/arm/aarch64/include/kvm/kvm-cpu-arch.h > index 8dfb82e..2b2c1ff 100644 > --- a/arm/aarch64/include/kvm/kvm-cpu-arch.h > +++ b/arm/aarch64/include/kvm/kvm-cpu-arch.h > @@ -19,5 +19,6 @@ > > void kvm_cpu__select_features(struct kvm *kvm, struct kvm_vcpu_init *init); > int kvm_cpu__configure_features(struct kvm_cpu *vcpu); > +int kvm_cpu__setup_pvtime(struct kvm_cpu *vcpu); > > #endif /* KVM__KVM_CPU_ARCH_H */ > diff --git a/arm/aarch64/pvtime.c b/arm/aarch64/pvtime.c > new file mode 100644 > index 0000000..fdde683 > --- /dev/null > +++ b/arm/aarch64/pvtime.c > @@ -0,0 +1,103 @@ > +#include "kvm/kvm.h" > +#include "kvm/kvm-cpu.h" > +#include "kvm/util.h" > + > +#include <linux/byteorder.h> > +#include <linux/types.h> > + > +#define ARM_PVTIME_STRUCT_SIZE (64) > + > +struct pvtime_data_priv { > + bool is_supported; > + char *usr_mem; > +}; > + > +static struct pvtime_data_priv pvtime_data = { > + .is_supported = true, > + .usr_mem = NULL > +}; > + > +static int pvtime__alloc_region(struct kvm *kvm) > +{ > + char *mem; > + int ret = 0; > + > + mem = mmap(NULL, ARM_PVTIME_MMIO_SIZE, PROT_RW, > + MAP_ANON_NORESERVE, -1, 0); > + if (mem == MAP_FAILED) > + return -errno; > + > + ret = kvm__register_dev_mem(kvm, ARM_PVTIME_MMIO_BASE, > + ARM_PVTIME_MMIO_SIZE, mem); > + if (ret) { > + munmap(mem, ARM_PVTIME_MMIO_SIZE); > + return ret; > + } > + > + pvtime_data.usr_mem = mem; > + return ret; > +} > + > +static int pvtime__teardown_region(struct kvm *kvm) > +{ > + if (pvtime_data.usr_mem == NULL) > + return 0; > + > + kvm__destroy_mem(kvm, ARM_PVTIME_MMIO_BASE, > + ARM_PVTIME_MMIO_SIZE, pvtime_data.usr_mem); > + munmap(pvtime_data.usr_mem, ARM_PVTIME_MMIO_SIZE); > + pvtime_data.usr_mem = NULL; > + return 0; > +} > + > +dev_exit(pvtime__teardown_region); This looks awkward: pvtime initialization is done in kvm_cpu__arch_init(), but teardown is done in the device exit stage. I think it would be better to choose one approach and stick with it: (1) keep initialization in kvm_cpu__arch_init() and move teardown to kvm_cpu__delete(); or (2) treat pvtime as a device, move the code to hw/pvtime.c, compile the file only for arm64 and move initialization to dev_init() (and keep teardown in dev_exit()). I have no preference for either, but I think a consistent approach to enabling pvtime is desirable. Thanks, Alex