Re: [PATCH v2 1/2] KVM: arm64: Move __adjust_pc out of line

Alexandru Elisei
2021-05-14T14:07:10Z

Hi Marc,

On 5/14/21 11:40 AM, Marc Zyngier wrote:
> In order to make it easy to call __adjust_pc() from the EL1 code
> (in the case of nVHE), rename it to __kvm_adjust_pc() and move
> it out of line.
>
> No expected functional change.

Looks good to me. Ran the kvm-unit-tests test selftest-vectors-kernel, which goes
out of its way to trigger an undefined exception, compiled for arm and arm64,
under VHE, nVHE and protected modes on an odroid-c4, everything worked as expected:

Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>

Thanks,

Alex

>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Cc: stable@vger.kernel.org # 5.11
> ---
> arch/arm64/include/asm/kvm_asm.h | 2 ++
> arch/arm64/kvm/hyp/exception.c | 18 +++++++++++++++++-
> arch/arm64/kvm/hyp/include/hyp/adjust_pc.h | 18 ------------------
> arch/arm64/kvm/hyp/nvhe/switch.c | 3 +--
> arch/arm64/kvm/hyp/vhe/switch.c | 3 +--
> 5 files changed, 21 insertions(+), 23 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> index cf8df032b9c3..d5b11037401d 100644
> --- a/arch/arm64/include/asm/kvm_asm.h
> +++ b/arch/arm64/include/asm/kvm_asm.h
> @@ -201,6 +201,8 @@ extern void __kvm_timer_set_cntvoff(u64 cntvoff);
>
> extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
>
> +extern void __kvm_adjust_pc(struct kvm_vcpu *vcpu);
> +
> extern u64 __vgic_v3_get_gic_config(void);
> extern u64 __vgic_v3_read_vmcr(void);
> extern void __vgic_v3_write_vmcr(u32 vmcr);
> diff --git a/arch/arm64/kvm/hyp/exception.c b/arch/arm64/kvm/hyp/exception.c
> index 73629094f903..0812a496725f 100644
> --- a/arch/arm64/kvm/hyp/exception.c
> +++ b/arch/arm64/kvm/hyp/exception.c
> @@ -296,7 +296,7 @@ static void enter_exception32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset)
> *vcpu_pc(vcpu) = vect_offset;
> }
>
> -void kvm_inject_exception(struct kvm_vcpu *vcpu)
> +static void kvm_inject_exception(struct kvm_vcpu *vcpu)
> {
> if (vcpu_el1_is_32bit(vcpu)) {
> switch (vcpu->arch.flags & KVM_ARM64_EXCEPT_MASK) {
> @@ -329,3 +329,19 @@ void kvm_inject_exception(struct kvm_vcpu *vcpu)
> }
> }
> }
> +
> +/*
> + * Adjust the guest PC on entry, depending on flags provided by EL1
> + * for the purpose of emulation (MMIO, sysreg) or exception injection.
> + */
> +void __kvm_adjust_pc(struct kvm_vcpu *vcpu)
> +{
> + if (vcpu->arch.flags & KVM_ARM64_PENDING_EXCEPTION) {
> + kvm_inject_exception(vcpu);
> + vcpu->arch.flags &= ~(KVM_ARM64_PENDING_EXCEPTION |
> + KVM_ARM64_EXCEPT_MASK);
> + } else if (vcpu->arch.flags & KVM_ARM64_INCREMENT_PC) {
> + kvm_skip_instr(vcpu);
> + vcpu->arch.flags &= ~KVM_ARM64_INCREMENT_PC;
> + }
> +}
> diff --git a/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h b/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h
> index 61716359035d..4fdfeabefeb4 100644
> --- a/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h
> +++ b/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h
> @@ -13,8 +13,6 @@
> #include <asm/kvm_emulate.h>
> #include <asm/kvm_host.h>
>
> -void kvm_inject_exception(struct kvm_vcpu *vcpu);
> -
> static inline void kvm_skip_instr(struct kvm_vcpu *vcpu)
> {
> if (vcpu_mode_is_32bit(vcpu)) {
> @@ -43,22 +41,6 @@ static inline void __kvm_skip_instr(struct kvm_vcpu *vcpu)
> write_sysreg_el2(*vcpu_pc(vcpu), SYS_ELR);
> }
>
> -/*
> - * Adjust the guest PC on entry, depending on flags provided by EL1
> - * for the purpose of emulation (MMIO, sysreg) or exception injection.
> - */
> -static inline void __adjust_pc(struct kvm_vcpu *vcpu)
> -{
> - if (vcpu->arch.flags & KVM_ARM64_PENDING_EXCEPTION) {
> - kvm_inject_exception(vcpu);
> - vcpu->arch.flags &= ~(KVM_ARM64_PENDING_EXCEPTION |
> - KVM_ARM64_EXCEPT_MASK);
> - } else if (vcpu->arch.flags & KVM_ARM64_INCREMENT_PC) {
> - kvm_skip_instr(vcpu);
> - vcpu->arch.flags &= ~KVM_ARM64_INCREMENT_PC;
> - }
> -}
> -
> /*
> * Skip an instruction while host sysregs are live.
> * Assumes host is always 64-bit.
> diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
> index e9f6ea704d07..f7af9688c1f7 100644
> --- a/arch/arm64/kvm/hyp/nvhe/switch.c
> +++ b/arch/arm64/kvm/hyp/nvhe/switch.c
> @@ -4,7 +4,6 @@
> * Author: Marc Zyngier <marc.zyngier@arm.com>
> */
>
> -#include <hyp/adjust_pc.h>
> #include <hyp/switch.h>
> #include <hyp/sysreg-sr.h>
>
> @@ -201,7 +200,7 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
> */
> __debug_save_host_buffers_nvhe(vcpu);
>
> - __adjust_pc(vcpu);
> + __kvm_adjust_pc(vcpu);
>
> /*
> * We must restore the 32-bit state before the sysregs, thanks
> diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
> index 7b8f7db5c1ed..b3229924d243 100644
> --- a/arch/arm64/kvm/hyp/vhe/switch.c
> +++ b/arch/arm64/kvm/hyp/vhe/switch.c
> @@ -4,7 +4,6 @@
> * Author: Marc Zyngier <marc.zyngier@arm.com>
> */
>
> -#include <hyp/adjust_pc.h>
> #include <hyp/switch.h>
>
> #include <linux/arm-smccc.h>
> @@ -132,7 +131,7 @@ static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
> __load_guest_stage2(vcpu->arch.hw_mmu);
> __activate_traps(vcpu);
>
> - __adjust_pc(vcpu);
> + __kvm_adjust_pc(vcpu);
>
> sysreg_restore_guest_state_vhe(guest_ctxt);
> __debug_switch_to_guest(vcpu);