Hi Marc,
On Thu, Apr 24, 2014 at 07:17:23PM +0100, Marc Zyngier wrote:
> Implement the kcm_cpu__get_endianness call for both AArch32 and
s/kcm/kvm/
> AArch64, and advertise the bi-endianness support.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> ---
> tools/kvm/arm/aarch32/kvm-cpu.c | 14 +++++++++++++
> tools/kvm/arm/aarch64/include/kvm/kvm-cpu-arch.h | 2 ++
> tools/kvm/arm/aarch64/kvm-cpu.c | 25 ++++++++++++++++++++++++
> tools/kvm/arm/include/arm-common/kvm-arch.h | 2 ++
> 4 files changed, 43 insertions(+)
>
> diff --git a/tools/kvm/arm/aarch32/kvm-cpu.c b/tools/kvm/arm/aarch32/kvm-cpu.c
> index bd71037..464b473 100644
> --- a/tools/kvm/arm/aarch32/kvm-cpu.c
> +++ b/tools/kvm/arm/aarch32/kvm-cpu.c
> @@ -1,5 +1,6 @@
> #include "kvm/kvm-cpu.h"
> #include "kvm/kvm.h"
> +#include "kvm/virtio.h"
>
> #include <asm/ptrace.h>
>
> @@ -76,6 +77,19 @@ void kvm_cpu__reset_vcpu(struct kvm_cpu *vcpu)
> die_perror("KVM_SET_ONE_REG failed (pc)");
> }
>
> +int kvm_cpu__get_endianness(struct kvm_cpu *vcpu)
> +{
> + struct kvm_one_reg reg;
> + u32 data;
> +
> + reg.id = ARM_CORE_REG(usr_regs.ARM_cpsr);
> + reg.addr = (u64)(unsigned long)&data;
> + if (ioctl(vcpu->vcpu_fd, KVM_GET_ONE_REG, ®) < 0)
> + die("KVM_GET_ONE_REG failed (cpsr)");
> +
> + return (data & PSR_E_BIT) ? VIRTIO_ENDIAN_BE : VIRTIO_ENDIAN_LE;
> +}
> +
> void kvm_cpu__show_code(struct kvm_cpu *vcpu)
> {
> struct kvm_one_reg reg;
> diff --git a/tools/kvm/arm/aarch64/include/kvm/kvm-cpu-arch.h b/tools/kvm/arm/aarch64/include/kvm/kvm-cpu-arch.h
> index 7d70c3b..ed7da45 100644
> --- a/tools/kvm/arm/aarch64/include/kvm/kvm-cpu-arch.h
> +++ b/tools/kvm/arm/aarch64/include/kvm/kvm-cpu-arch.h
> @@ -13,5 +13,7 @@
> #define ARM_MPIDR_HWID_BITMASK 0xFF00FFFFFFUL
> #define ARM_CPU_ID 3, 0, 0, 0
> #define ARM_CPU_ID_MPIDR 5
> +#define ARM_CPU_CTRL 3, 0, 1, 0
> +#define ARM_CPU_CTRL_SCTLR 0
>
> #endif /* KVM__KVM_CPU_ARCH_H */
> diff --git a/tools/kvm/arm/aarch64/kvm-cpu.c b/tools/kvm/arm/aarch64/kvm-cpu.c
> index 059e42c..b3ce2c8 100644
> --- a/tools/kvm/arm/aarch64/kvm-cpu.c
> +++ b/tools/kvm/arm/aarch64/kvm-cpu.c
> @@ -1,12 +1,16 @@
> #include "kvm/kvm-cpu.h"
> #include "kvm/kvm.h"
> +#include "kvm/virtio.h"
>
> #include <asm/ptrace.h>
>
> #define COMPAT_PSR_F_BIT 0x00000040
> #define COMPAT_PSR_I_BIT 0x00000080
> +#define COMPAT_PSR_E_BIT 0x00000200
> #define COMPAT_PSR_MODE_SVC 0x00000013
>
> +#define SCTLR_EL1_EE_MASK (1 << 25)
> +
> #define ARM64_CORE_REG(x) (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \
> KVM_REG_ARM_CORE | KVM_REG_ARM_CORE_REG(x))
>
> @@ -133,6 +137,27 @@ void kvm_cpu__reset_vcpu(struct kvm_cpu *vcpu)
> return reset_vcpu_aarch64(vcpu);
> }
>
> +int kvm_cpu__get_endianness(struct kvm_cpu *vcpu)
> +{
> + struct kvm_one_reg reg;
> + u64 data;
> +
> + reg.id = ARM64_CORE_REG(regs.pstate);
> + reg.addr = (u64)&data;
> + if (ioctl(vcpu->vcpu_fd, KVM_GET_ONE_REG, ®) < 0)
> + die("KVM_GET_ONE_REG failed (spsr[EL1])");
This bit hurt for a while ;) Can you add a comment mentioning SETEND for
AArch32 guests please?
> + if (data & PSR_MODE32_BIT)
> + return (data & COMPAT_PSR_E_BIT) ? VIRTIO_ENDIAN_BE : VIRTIO_ENDIAN_LE;
> +
> + reg.id = ARM64_SYS_REG(ARM_CPU_CTRL, ARM_CPU_CTRL_SCTLR); /* SCTLR_EL1 */
We should probably just rename ARM_CPU_CTRL_SCTLR that to include the _EL1
suffix.
> + reg.addr = (u64)&data;
> + if (ioctl(vcpu->vcpu_fd, KVM_GET_ONE_REG, ®) < 0)
> + die("KVM_GET_ONE_REG failed (SCTLR_EL1)");
> +
> + return (data & SCTLR_EL1_EE_MASK) ? VIRTIO_ENDIAN_BE : VIRTIO_ENDIAN_LE;
This rules out guests where userspace and kernelspace can run with different
endinness. Whilst Linux doesn't currently do this, can we support it here?
It all gets a bit hairy if the guest is using a stage-1 SMMU to let
userspace play with a virtio device...
Will
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