Re: [PATCH v4 18/43] arm64: RME: Handle realm enter/exit

[Steven Price <steven.price@arm.com>]

On 22/08/2024 04:53, Aneesh Kumar K.V wrote:
> Steven Price <steven.price@arm.com> writes:
> 
>> Entering a realm is done using a SMC call to the RMM. On exit the
>> exit-codes need to be handled slightly differently to the normal KVM
>> path so define our own functions for realm enter/exit and hook them
>> in if the guest is a realm guest.
>>
>> Signed-off-by: Steven Price <steven.price@arm.com>
>> ---
>> Changes since v2:
>>  * realm_set_ipa_state() now provides an output parameter for the
>>    top_iap that was changed. Use this to signal the VMM with the correct
>>    range that has been transitioned.
>>  * Adapt to previous patch changes.
>> ---
>>  arch/arm64/include/asm/kvm_rme.h |   3 +
>>  arch/arm64/kvm/Makefile          |   2 +-
>>  arch/arm64/kvm/arm.c             |  19 +++-
>>  arch/arm64/kvm/rme-exit.c        | 181 +++++++++++++++++++++++++++++++
>>  arch/arm64/kvm/rme.c             |  11 ++
>>  5 files changed, 210 insertions(+), 6 deletions(-)
>>  create mode 100644 arch/arm64/kvm/rme-exit.c
>>
>> diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
>> index c064bfb080ad..0e44b20cfa48 100644
>> --- a/arch/arm64/include/asm/kvm_rme.h
>> +++ b/arch/arm64/include/asm/kvm_rme.h
>> @@ -96,6 +96,9 @@ void kvm_realm_destroy_rtts(struct kvm *kvm, u32 ia_bits);
>>  int kvm_create_rec(struct kvm_vcpu *vcpu);
>>  void kvm_destroy_rec(struct kvm_vcpu *vcpu);
>>  
>> +int kvm_rec_enter(struct kvm_vcpu *vcpu);
>> +int handle_rme_exit(struct kvm_vcpu *vcpu, int rec_run_status);
>> +
>>  void kvm_realm_unmap_range(struct kvm *kvm,
>>  			   unsigned long ipa,
>>  			   u64 size,
>> diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
>> index 5e79e5eee88d..9f893e86cac9 100644
>> --- a/arch/arm64/kvm/Makefile
>> +++ b/arch/arm64/kvm/Makefile
>> @@ -21,7 +21,7 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
>>  	 vgic/vgic-mmio.o vgic/vgic-mmio-v2.o \
>>  	 vgic/vgic-mmio-v3.o vgic/vgic-kvm-device.o \
>>  	 vgic/vgic-its.o vgic/vgic-debug.o \
>> -	 rme.o
>> +	 rme.o rme-exit.o
>>  
>>  kvm-$(CONFIG_HW_PERF_EVENTS)  += pmu-emul.o pmu.o
>>  kvm-$(CONFIG_ARM64_PTR_AUTH)  += pauth.o
>> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
>> index 568e9e6e5a4e..e8dabb996705 100644
>> --- a/arch/arm64/kvm/arm.c
>> +++ b/arch/arm64/kvm/arm.c
>> @@ -1282,7 +1282,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>>  		trace_kvm_entry(*vcpu_pc(vcpu));
>>  		guest_timing_enter_irqoff();
>>  
>> -		ret = kvm_arm_vcpu_enter_exit(vcpu);
>> +		if (vcpu_is_rec(vcpu))
>> +			ret = kvm_rec_enter(vcpu);
>> +		else
>> +			ret = kvm_arm_vcpu_enter_exit(vcpu);
>>  
>>  		vcpu->mode = OUTSIDE_GUEST_MODE;
>>  		vcpu->stat.exits++;
>> @@ -1336,10 +1339,13 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>>  
>>  		local_irq_enable();
>>  
>> -		trace_kvm_exit(ret, kvm_vcpu_trap_get_class(vcpu), *vcpu_pc(vcpu));
>> -
>>  		/* Exit types that need handling before we can be preempted */
>> -		handle_exit_early(vcpu, ret);
>> +		if (!vcpu_is_rec(vcpu)) {
>> +			trace_kvm_exit(ret, kvm_vcpu_trap_get_class(vcpu),
>> +				       *vcpu_pc(vcpu));
>> +
>> +			handle_exit_early(vcpu, ret);
>> +		}
>>  
>>  		preempt_enable();
>>  
>> @@ -1362,7 +1368,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>>  			ret = ARM_EXCEPTION_IL;
>>  		}
>>  
>> -		ret = handle_exit(vcpu, ret);
>> +		if (vcpu_is_rec(vcpu))
>> +			ret = handle_rme_exit(vcpu, ret);
>> +		else
>> +			ret = handle_exit(vcpu, ret);
>>  	}
>>
> 
> like kvm_rec_enter, should we name this as handle_rec_exit()?

Fair enough, will rename.

Steve

> 
>  arch/arm64/include/asm/kvm_rme.h | 2 +-
>  arch/arm64/kvm/arm.c             | 2 +-
>  arch/arm64/kvm/rme-exit.c        | 2 +-
>  3 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
> index a72e06cf4ea6..cd42c19ca21d 100644
> --- a/arch/arm64/include/asm/kvm_rme.h
> +++ b/arch/arm64/include/asm/kvm_rme.h
> @@ -102,7 +102,7 @@ int kvm_create_rec(struct kvm_vcpu *vcpu);
>  void kvm_destroy_rec(struct kvm_vcpu *vcpu);
>  
>  int kvm_rec_enter(struct kvm_vcpu *vcpu);
> -int handle_rme_exit(struct kvm_vcpu *vcpu, int rec_run_status);
> +int handle_rec_exit(struct kvm_vcpu *vcpu, int rec_run_status);
>  
>  void kvm_realm_unmap_range(struct kvm *kvm,
>  			   unsigned long ipa,
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 05d9062470c2..1e34541d88db 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -1391,7 +1391,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>  		}
>  
>  		if (vcpu_is_rec(vcpu))
> -			ret = handle_rme_exit(vcpu, ret);
> +			ret = handle_rec_exit(vcpu, ret);
>  		else
>  			ret = handle_exit(vcpu, ret);
>  	}
> diff --git a/arch/arm64/kvm/rme-exit.c b/arch/arm64/kvm/rme-exit.c
> index 0940575b0a14..f888cfe72dfa 100644
> --- a/arch/arm64/kvm/rme-exit.c
> +++ b/arch/arm64/kvm/rme-exit.c
> @@ -156,7 +156,7 @@ static void update_arch_timer_irq_lines(struct kvm_vcpu *vcpu)
>   * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
>   * proper exit to userspace.
>   */
> -int handle_rme_exit(struct kvm_vcpu *vcpu, int rec_run_ret)
> +int handle_rec_exit(struct kvm_vcpu *vcpu, int rec_run_ret)
>  {
>  	struct realm_rec *rec = &vcpu->arch.rec;
>  	u8 esr_ec = ESR_ELx_EC(rec->run->exit.esr);