Hi,
On Tue, Feb 22, 2022 at 10:08:30AM +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. The exact format of the structure stored by the
> hypervisor is described in the ARM DEN0057A document.
>
> Signed-off-by: Sebastian Ene <sebastianene@xxxxxxxxxx>
> ---
> Changelog since v2:
> - Moved the AARCH64_PVTIME_* definitions from arm-common/kvm-arch.h to
> arm64/pvtime.c as pvtime is only available for arm64.
>
> Changelog since v1:
> - Removed the pvtime.h header file and moved the definitions to kvm-cpu-arch.h
> Verified if the stolen time capability is supported before allocating
> and mapping the memory.
>
> Makefile | 1 +
> arm/aarch64/arm-cpu.c | 1 +
> arm/aarch64/include/kvm/kvm-cpu-arch.h | 1 +
> arm/aarch64/pvtime.c | 89 ++++++++++++++++++++++++++
> arm/kvm-cpu.c | 14 ++--
> 5 files changed, 99 insertions(+), 7 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..326fb20 100644
> --- a/arm/aarch64/arm-cpu.c
> +++ b/arm/aarch64/arm-cpu.c
> @@ -22,6 +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;
> + kvm_cpu__setup_pvtime(vcpu);
> return 0;
> }
>
> diff --git a/arm/aarch64/include/kvm/kvm-cpu-arch.h b/arm/aarch64/include/kvm/kvm-cpu-arch.h
> index 8dfb82e..b57d6e6 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);
> +void 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..247e4f3
> --- /dev/null
> +++ b/arm/aarch64/pvtime.c
> @@ -0,0 +1,89 @@
> +#include "kvm/kvm.h"
> +#include "kvm/kvm-cpu.h"
> +#include "kvm/util.h"
> +
> +#include <linux/byteorder.h>
> +#include <linux/types.h>
> +
> +#define AARCH64_PVTIME_IPA_MAX_SIZE SZ_64K
> +#define AARCH64_PVTIME_IPA_START (ARM_MEMORY_AREA - \
> + AARCH64_PVTIME_IPA_MAX_SIZE)
This doesn't change the fact that it overlaps with KVM_PCI_MMIO_AREA, which is
exposed to the guest in the DTB (see my reply to v2).
Thanks,
Alex
> +#define AARCH64_PVTIME_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, AARCH64_PVTIME_IPA_MAX_SIZE, PROT_RW,
> + MAP_ANON_NORESERVE, -1, 0);
> + if (mem == MAP_FAILED)
> + return -ENOMEM;
> +
> + ret = kvm__register_dev_mem(kvm, AARCH64_PVTIME_IPA_START,
> + AARCH64_PVTIME_IPA_MAX_SIZE, mem);
> + if (ret) {
> + munmap(mem, AARCH64_PVTIME_IPA_MAX_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, AARCH64_PVTIME_IPA_START,
> + AARCH64_PVTIME_IPA_MAX_SIZE, pvtime_data.usr_mem);
> + munmap(pvtime_data.usr_mem, AARCH64_PVTIME_IPA_MAX_SIZE);
> + pvtime_data.usr_mem = NULL;
> + return 0;
> +}
> +
> +void kvm_cpu__setup_pvtime(struct kvm_cpu *vcpu)
> +{
> + int ret;
> + u64 pvtime_guest_addr = AARCH64_PVTIME_IPA_START + vcpu->cpu_id *
> + AARCH64_PVTIME_SIZE;
> + struct kvm_device_attr pvtime_attr = (struct kvm_device_attr) {
> + .group = KVM_ARM_VCPU_PVTIME_CTRL,
> + .addr = KVM_ARM_VCPU_PVTIME_IPA
> + };
> +
> + if (!pvtime_data.is_supported)
> + return;
> +
> + ret = ioctl(vcpu->vcpu_fd, KVM_HAS_DEVICE_ATTR, &pvtime_attr);
> + if (ret)
> + goto out_err;
> +
> + if (!pvtime_data.usr_mem) {
> + ret = pvtime__alloc_region(vcpu->kvm);
> + if (ret)
> + goto out_err;
> + }
> +
> + pvtime_attr.addr = (u64)&pvtime_guest_addr;
> + ret = ioctl(vcpu->vcpu_fd, KVM_SET_DEVICE_ATTR, &pvtime_attr);
> + if (!ret)
> + return;
> +
> + pvtime__teardown_region(vcpu->kvm);
> +out_err:
> + pvtime_data.is_supported = false;
> +}
> +
> +dev_exit(pvtime__teardown_region);
> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
> index 6a2408c..84ac1e9 100644
> --- a/arm/kvm-cpu.c
> +++ b/arm/kvm-cpu.c
> @@ -116,6 +116,13 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id)
> die("Unable to find matching target");
> }
>
> + /* Populate the vcpu structure. */
> + vcpu->kvm = kvm;
> + vcpu->cpu_id = cpu_id;
> + vcpu->cpu_type = vcpu_init.target;
> + vcpu->cpu_compatible = target->compatible;
> + vcpu->is_running = true;
> +
> if (err || target->init(vcpu))
> die("Unable to initialise vcpu");
>
> @@ -125,13 +132,6 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id)
> vcpu->ring = (void *)vcpu->kvm_run +
> (coalesced_offset * PAGE_SIZE);
>
> - /* Populate the vcpu structure. */
> - vcpu->kvm = kvm;
> - vcpu->cpu_id = cpu_id;
> - vcpu->cpu_type = vcpu_init.target;
> - vcpu->cpu_compatible = target->compatible;
> - vcpu->is_running = true;
> -
> if (kvm_cpu__configure_features(vcpu))
> die("Unable to configure requested vcpu features");
>
> --
> 2.35.1.473.g83b2b277ed-goog
>
