Subject: Re: [RFC PATCH 1/9] KVM: PPC: Book3S 64: move KVM interrupt entry to a common entry point

From: Daniel Axtens <[email-masked]>
Date: Fri, 19 Feb 2021 16:18:19 +1100

Hi Nick,

> +++ b/arch/powerpc/kvm/book3s_64_entry.S
> @@ -0,0 +1,34 @@
> +#include <asm/cache.h>
> +#include <asm/ppc_asm.h>
> +#include <asm/kvm_asm.h>
> +#include <asm/reg.h>
> +#include <asm/asm-offsets.h>
> +#include <asm/kvm_book3s_asm.h>
> +
> +/*
> + * We come here from the first-level interrupt handlers.
> + */
> +.global	kvmppc_interrupt
> +.balign IFETCH_ALIGN_BYTES
> +kvmppc_interrupt:
> +	/*
> +	 * Register contents:

Clearly r9 contains some data at this point, and I think it's guest r9
because of what you say later on in
book3s_hv_rmhandlers.S::kvmppc_interrupt_hv. Is that right? Should that
be documented in this comment as well?

> +	 * R12		= (guest CR << 32) | interrupt vector
> +	 * R13		= PACA
> +	 * guest R12 saved in shadow VCPU SCRATCH0
> +	 * guest R13 saved in SPRN_SCRATCH0
> +	 */
> +#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
> +	std	r9, HSTATE_SCRATCH2(r13)
> +	lbz	r9, HSTATE_IN_GUEST(r13)
> +	cmpwi	r9, KVM_GUEST_MODE_HOST_HV
> +	beq	kvmppc_bad_host_intr
> +#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
> +	cmpwi	r9, KVM_GUEST_MODE_GUEST
> +	ld	r9, HSTATE_SCRATCH2(r13)
> +	beq	kvmppc_interrupt_pr
> +#endif
> +	b	kvmppc_interrupt_hv
> +#else
> +	b	kvmppc_interrupt_pr
> +#endif

Apart from that I had a look and convinced myself that the code will
behave the same as before. On that basis:

Reviewed-by: Daniel Axtens <[email-masked]>

Kind regards,
Daniel