On 24/04/13 00:02, Christoffer Dall wrote:
> 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
I still hold that it makes things more readable.
>> +}
>> +
>> 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 ?
Not sure. If you ended up here, it means you tried to start a 32bit
guest on a 64bit-only CPU, despite KVM_CAP_ARM_EL1_32BIT telling you
that your CPU is not 32bit capable.
This is clearly an invalid input, isn't it?
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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