Re: [kvm-unit-tests PATCH v5 2/6] s390x: add function to set DAT mode for all interrupts

Claudio Imbrenda
2023-07-13T08:33:28Z

On Wed, 12 Jul 2023 13:41:45 +0200
Nico Boehr <nrb@linux.ibm.com> wrote:

[...]

> +/**
> + * irq_set_dat_mode - Set the DAT mode of all interrupt handlers, except for
> + * restart.
> + * This will update the DAT mode and address space mode of all interrupt new
> + * PSWs.
> + *
> + * Since enabling DAT needs initalized CRs and the restart new PSW is often used
> + * to initalize CRs, the restart new PSW is never touched to avoid the chicken
> + * and egg situation.
> + *
> + * @dat specifies whether to use DAT or not
> + * @as specifies the address space mode to use - one of AS_PRIM, AS_ACCR,

please mention here that as will not be set if dat == false

> + * AS_SECN or AS_HOME.
> + */
> +void irq_set_dat_mode(bool dat, uint64_t as)
> +{
> + struct psw* irq_psws[] = {
> + OPAQUE_PTR(GEN_LC_EXT_NEW_PSW),
> + OPAQUE_PTR(GEN_LC_SVC_NEW_PSW),
> + OPAQUE_PTR(GEN_LC_PGM_NEW_PSW),
> + OPAQUE_PTR(GEN_LC_MCCK_NEW_PSW),
> + OPAQUE_PTR(GEN_LC_IO_NEW_PSW),
> + };
> + struct psw *psw;
> +
> + assert(as == AS_PRIM || as == AS_ACCR || as == AS_SECN || as == AS_HOME);
> +
> + for (size_t i = 0; i < ARRAY_SIZE(irq_psws); i++) {
> + psw = irq_psws[i];
> + psw->dat = dat;
> + if (dat)
> + psw->as = as;
> + }
> +}
> +
> static void fixup_pgm_int(struct stack_frame_int *stack)
> {
> /* If we have an error on SIE we directly move to sie_exit */
> diff --git a/lib/s390x/mmu.c b/lib/s390x/mmu.c
> index b474d7021d3f..199bd3fbc9c8 100644
> --- a/lib/s390x/mmu.c
> +++ b/lib/s390x/mmu.c
> @@ -12,6 +12,7 @@
> #include <asm/pgtable.h>
> #include <asm/arch_def.h>
> #include <asm/barrier.h>
> +#include <asm/interrupt.h>
> #include <vmalloc.h>
> #include "mmu.h"
>
> @@ -41,8 +42,8 @@ static void mmu_enable(pgd_t *pgtable)
> /* enable dat (primary == 0 set as default) */
> enable_dat();
>
> - /* we can now also use DAT unconditionally in our PGM handler */
> - lowcore.pgm_new_psw.mask |= PSW_MASK_DAT;
> + /* we can now also use DAT in all interrupt handlers */
> + irq_set_dat_mode(IRQ_DAT_ON, AS_PRIM);
> }
>
> /*