diff mbox series

[RFC,08/27] KVM: arm64: Make kvm_call_hyp() a function call at Hyp

Message ID 20201117181607.1761516-9-qperret@google.com
State Superseded
Headers show
Series [RFC,01/27] arm64: lib: Annotate {clear,copy}_page() as position-independent | expand

Commit Message

Quentin Perret Nov. 17, 2020, 6:15 p.m. UTC
kvm_call_hyp() has some logic to issue a function call or a hypercall
depending the EL at which the kernel is running. However, all the code
compiled under __KVM_NVHE_HYPERVISOR__ is guaranteed to run only at EL2,
and in this case a simple function call is needed.

Add ifdefery to kvm_host.h to symplify kvm_call_hyp() in .hyp.text.

Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/include/asm/kvm_host.h | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

David Brazdil Nov. 23, 2020, 12:51 p.m. UTC | #1
On Tue, Nov 17, 2020 at 06:15:48PM +0000, 'Quentin Perret' via kernel-team wrote:
> kvm_call_hyp() has some logic to issue a function call or a hypercall

> depending the EL at which the kernel is running. However, all the code

> compiled under __KVM_NVHE_HYPERVISOR__ is guaranteed to run only at EL2,

> and in this case a simple function call is needed.

> 

> Add ifdefery to kvm_host.h to symplify kvm_call_hyp() in .hyp.text.

> 

> Signed-off-by: Quentin Perret <qperret@google.com>

> ---

>  arch/arm64/include/asm/kvm_host.h | 6 ++++++

>  1 file changed, 6 insertions(+)

> 

> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h

> index ac11adab6602..7a5d5f4b3351 100644

> --- a/arch/arm64/include/asm/kvm_host.h

> +++ b/arch/arm64/include/asm/kvm_host.h

> @@ -557,6 +557,7 @@ int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);

>  void kvm_arm_halt_guest(struct kvm *kvm);

>  void kvm_arm_resume_guest(struct kvm *kvm);

>  

> +#ifndef __KVM_NVHE_HYPERVISOR__

>  #define kvm_call_hyp_nvhe(f, ...)						\

>  	({								\

>  		struct arm_smccc_res res;				\

> @@ -596,6 +597,11 @@ void kvm_arm_resume_guest(struct kvm *kvm);

>  									\

>  		ret;							\

>  	})

> +#else /* __KVM_NVHE_HYPERVISOR__ */

> +#define kvm_call_hyp(f, ...) f(__VA_ARGS__)

> +#define kvm_call_hyp_ret(f, ...) f(__VA_ARGS__)

> +#define kvm_call_hyp_nvhe(f, ...) f(__VA_ARGS__)

> +#endif /* __KVM_NVHE_HYPERVISOR__ */


I was hoping we could define this as the following instead. That would require
adding host-side declarations of all functions currently called with _nvhe.

#define kvm_call_hyp_nvhe(f, ...)					\
+	is_nvhe_hyp_code() ? f(__VA_ARGS__) :				\
	({								\
		struct arm_smccc_res res;				\
									\
		arm_smccc_1_1_hvc(KVM_HOST_SMCCC_FUNC(f),		\
				##__VA_ARGS__, &res);			\
		WARN_ON(res.a0 != SMCCC_RET_SUCCESS);			\
									\
		res.a1;							\
	})

Up to you what you think is cleaner, just my 2 cents...
diff mbox series

Patch

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index ac11adab6602..7a5d5f4b3351 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -557,6 +557,7 @@  int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);
 void kvm_arm_halt_guest(struct kvm *kvm);
 void kvm_arm_resume_guest(struct kvm *kvm);
 
+#ifndef __KVM_NVHE_HYPERVISOR__
 #define kvm_call_hyp_nvhe(f, ...)						\
 	({								\
 		struct arm_smccc_res res;				\
@@ -596,6 +597,11 @@  void kvm_arm_resume_guest(struct kvm *kvm);
 									\
 		ret;							\
 	})
+#else /* __KVM_NVHE_HYPERVISOR__ */
+#define kvm_call_hyp(f, ...) f(__VA_ARGS__)
+#define kvm_call_hyp_ret(f, ...) f(__VA_ARGS__)
+#define kvm_call_hyp_nvhe(f, ...) f(__VA_ARGS__)
+#endif /* __KVM_NVHE_HYPERVISOR__ */
 
 void force_vm_exit(const cpumask_t *mask);
 void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot);