Hi Marc,
On Sat, May 28, 2022 at 12:49 PM Marc Zyngier <maz@xxxxxxxxxx> wrote:
>
> We really don't want PENDING_EXCEPTION and INCREMENT_PC to ever be
> set at the same time, as they are mutually exclusive. Add checks
> that will generate a warning should this ever happen.
>
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> ---
> arch/arm64/include/asm/kvm_emulate.h | 1 +
> arch/arm64/kvm/hyp/nvhe/sys_regs.c | 2 ++
> arch/arm64/kvm/inject_fault.c | 8 ++++++++
> 3 files changed, 11 insertions(+)
>
> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index 46e631cd8d9e..861fa0b24a7f 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -473,6 +473,7 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu,
>
> static __always_inline void kvm_incr_pc(struct kvm_vcpu *vcpu)
> {
> + WARN_ON(vcpu_get_flag(vcpu, PENDING_EXCEPTION));
> vcpu_set_flag(vcpu, INCREMENT_PC);
> }
>
> diff --git a/arch/arm64/kvm/hyp/nvhe/sys_regs.c b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
> index 2841a2d447a1..04973984b6db 100644
> --- a/arch/arm64/kvm/hyp/nvhe/sys_regs.c
> +++ b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
> @@ -38,6 +38,8 @@ static void inject_undef64(struct kvm_vcpu *vcpu)
> *vcpu_pc(vcpu) = read_sysreg_el2(SYS_ELR);
> *vcpu_cpsr(vcpu) = read_sysreg_el2(SYS_SPSR);
>
> + WARN_ON(vcpu_get_flag(vcpu, INCREMENT_PC));
> +
> vcpu_set_flag(vcpu, PENDING_EXCEPTION);
> vcpu_set_flag(vcpu, EXCEPT_AA64_EL1_SYNC);
>
> diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
> index a9a7b513f3b0..2f4b9afc16ec 100644
> --- a/arch/arm64/kvm/inject_fault.c
> +++ b/arch/arm64/kvm/inject_fault.c
> @@ -20,6 +20,8 @@ static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr
> bool is_aarch32 = vcpu_mode_is_32bit(vcpu);
> u32 esr = 0;
>
> + WARN_ON(vcpu_get_flag(vcpu, INCREMENT_PC));
> +
Minor nit: While we're at it, should we just create a helper for
setting PENDING_EXCEPTION, same as we have for INCREMENT_PC? That
might make the code clearer and save us from the hassle of having this
WARN_ON before every instance of setting PENDING_EXCEPTION?
Cheers,
/fuad
> vcpu_set_flag(vcpu, PENDING_EXCEPTION);
> vcpu_set_flag(vcpu, EXCEPT_AA64_EL1_SYNC);
>
> @@ -51,6 +53,8 @@ static void inject_undef64(struct kvm_vcpu *vcpu)
> {
> u32 esr = (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT);
>
> + WARN_ON(vcpu_get_flag(vcpu, INCREMENT_PC));
> +
> vcpu_set_flag(vcpu, PENDING_EXCEPTION);
> vcpu_set_flag(vcpu, EXCEPT_AA64_EL1_SYNC);
>
> @@ -71,6 +75,8 @@ static void inject_undef64(struct kvm_vcpu *vcpu)
>
> static void inject_undef32(struct kvm_vcpu *vcpu)
> {
> + WARN_ON(vcpu_get_flag(vcpu, INCREMENT_PC));
> +
> vcpu_set_flag(vcpu, PENDING_EXCEPTION);
> vcpu_set_flag(vcpu, EXCEPT_AA32_UND);
> }
> @@ -94,6 +100,8 @@ static void inject_abt32(struct kvm_vcpu *vcpu, bool is_pabt, u32 addr)
>
> far = vcpu_read_sys_reg(vcpu, FAR_EL1);
>
> + WARN_ON(vcpu_get_flag(vcpu, INCREMENT_PC));
> +
> if (is_pabt) {
> vcpu_set_flag(vcpu, PENDING_EXCEPTION);
> vcpu_set_flag(vcpu, EXCEPT_AA32_IABT);
> --
> 2.34.1
>
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