On Mon, Apr 08, 2013 at 05:17:32PM +0100, Marc Zyngier wrote:
> Wire the init of a 32bit vcpu by allowing 32bit modes in pstate,
> and providing sensible defaults out of reset state.
>
> This feature is of course conditioned by the presence of 32bit
> capability on the physical CPU, and is checked by the KVM_CAP_ARM_EL1_32BIT
> capability.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> ---
> arch/arm64/include/asm/kvm_host.h | 2 +-
> arch/arm64/include/uapi/asm/kvm.h | 1 +
> arch/arm64/kvm/guest.c | 6 ++++++
> arch/arm64/kvm/reset.c | 25 ++++++++++++++++++++++++-
> include/uapi/linux/kvm.h | 1 +
> 5 files changed, 33 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index d44064d..c3ec107 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -34,7 +34,7 @@
> #include <asm/kvm_vgic.h>
> #include <asm/kvm_arch_timer.h>
>
> -#define KVM_VCPU_MAX_FEATURES 1
> +#define KVM_VCPU_MAX_FEATURES 2
>
> /* We don't currently support large pages. */
> #define KVM_HPAGE_GFN_SHIFT(x) 0
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index 5b1110c..5031f42 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -75,6 +75,7 @@ struct kvm_regs {
> #define KVM_VGIC_V2_CPU_SIZE 0x2000
>
> #define KVM_ARM_VCPU_POWER_OFF 0 /* CPU is started in OFF state */
> +#define KVM_ARM_VCPU_EL1_32BIT 1 /* CPU running a 32bit VM */
>
> struct kvm_vcpu_init {
> __u32 target;
> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
> index 47d3729..74ef7d5 100644
> --- a/arch/arm64/kvm/guest.c
> +++ b/arch/arm64/kvm/guest.c
> @@ -93,6 +93,12 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
> if (off == KVM_REG_ARM_CORE_REG(regs.pstate)) {
> unsigned long mode = (*(unsigned long *)valp) & COMPAT_PSR_MODE_MASK;
> switch (mode) {
> + case COMPAT_PSR_MODE_USR:
> + case COMPAT_PSR_MODE_FIQ:
> + case COMPAT_PSR_MODE_IRQ:
> + case COMPAT_PSR_MODE_SVC:
> + case COMPAT_PSR_MODE_ABT:
> + case COMPAT_PSR_MODE_UND:
> case PSR_MODE_EL0t:
> case PSR_MODE_EL1t:
> case PSR_MODE_EL1h:
> diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
> index bc33e76..a282d35 100644
> --- a/arch/arm64/kvm/reset.c
> +++ b/arch/arm64/kvm/reset.c
> @@ -35,11 +35,27 @@ static struct kvm_regs default_regs_reset = {
> .regs.pstate = PSR_MODE_EL1h | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT,
> };
>
> +static struct kvm_regs default_regs_reset32 = {
> + .regs.pstate = (COMPAT_PSR_MODE_SVC | COMPAT_PSR_A_BIT |
> + COMPAT_PSR_I_BIT | COMPAT_PSR_F_BIT),
> +};
> +
> +static bool cpu_has_32bit_el1(void)
> +{
> + u64 pfr0;
> +
> + pfr0 = read_cpuid(ID_AA64PFR0_EL1);
> + return !!(pfr0 & 0x20);
again we don't need the double negation
> +}
> +
> int kvm_arch_dev_ioctl_check_extention(long ext)
> {
> int r;
>
> switch (ext) {
> + case KVM_CAP_ARM_EL1_32BIT:
> + r = cpu_has_32bit_el1();
> + break;
> default:
> r = 0;
> }
> @@ -62,7 +78,14 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
>
> switch (vcpu->arch.target) {
> default:
> - cpu_reset = &default_regs_reset;
> + if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) {
> + if (!cpu_has_32bit_el1())
> + return -EINVAL;
I'm not sure EINVAL is appropriate here, the value specified was not
incorrect, it's that the hardware doesn't support it. ENXIO, ENODEV, and
add that in Documentation/virtual/kvm/api.txt ?
> + cpu_reset = &default_regs_reset32;
> + vcpu->arch.hcr_el2 &= ~HCR_RW;
> + } else {
> + cpu_reset = &default_regs_reset;
> + }
> break;
> }
>
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 2bf42b0..ce05763 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -665,6 +665,7 @@ struct kvm_ppc_smmu_info {
> #define KVM_CAP_PPC_EPR 86
> #define KVM_CAP_ARM_PSCI 87
> #define KVM_CAP_ARM_SET_DEVICE_ADDR 88
> +#define KVM_CAP_ARM_EL1_32BIT 89
>
> #ifdef KVM_CAP_IRQ_ROUTING
>
> --
> 1.8.1.4
>
>
>
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