Re: [kvm-unit-tests PATCH v3 4/7] s390x: Add function for checking diagnose intercepts

Nina Schoetterl-Glausch
2024-06-25T08:11:26Z

On Tue, 2024-06-25 at 12:14 +1000, Nicholas Piggin wrote:
> On Fri Jun 21, 2024 at 12:16 AM AEST, Nina Schoetterl-Glausch wrote:
> > sie_is_diag_icpt() checks if the intercept is due to an expected
> > diagnose call and is valid.
> > It subsumes pv_icptdata_check_diag.
> >
> > Signed-off-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
> > ---
> > lib/s390x/pv_icptdata.h | 42 --------------------------------
> > lib/s390x/sie.h | 12 ++++++++++
> > lib/s390x/sie.c | 53 +++++++++++++++++++++++++++++++++++++++++
> > s390x/pv-diags.c | 8 +++----
> > s390x/pv-icptcode.c | 11 ++++-----
> > s390x/pv-ipl.c | 7 +++---
> > 6 files changed, 76 insertions(+), 57 deletions(-)
> > delete mode 100644 lib/s390x/pv_icptdata.h

[...]

> > +bool sie_is_diag_icpt(struct vm *vm, unsigned int diag)
> > +{
> > + union {
> > + struct {
> > + uint64_t : 16;
> > + uint64_t ipa : 16;
> > + uint64_t ipb : 32;
> > + };
> > + struct {
> > + uint64_t : 16;
> > + uint64_t opcode : 8;
> > + uint64_t r_1 : 4;
> > + uint64_t r_2 : 4;
> > + uint64_t r_base : 4;
> > + uint64_t displace : 12;
> > + uint64_t zero : 16;
> > + };
> > + } instr = { .ipa = vm->sblk->ipa, .ipb = vm->sblk->ipb };
> > + uint8_t icptcode;
> > + uint64_t code;
> > +
> > + switch (diag) {
> > + case 0x44:
> > + case 0x9c:
> > + case 0x288:
> > + case 0x308:
> > + icptcode = ICPT_PV_NOTIFY;
> > + break;
> > + case 0x500:
> > + icptcode = ICPT_PV_INSTR;
> > + break;
> > + default:
> > + /* If a new diag is introduced add it to the cases above! */
> > + assert_msg(false, "unknown diag");
> > + }
> > +
> > + if (sie_is_pv(vm)) {
> > + if (instr.r_1 != 0 || instr.r_2 != 2 || instr.r_base != 5)
> > + return false;
> > + if (instr.displace)
> > + return false;
> > + } else {
> > + icptcode = ICPT_INST;
> > + }
> > + if (vm->sblk->icptcode != icptcode)
> > + return false;
> > + if (instr.opcode != 0x83 || instr.zero)
> > + return false;
> > + code = instr.r_base ? vm->save_area.guest.grs[instr.r_base] : 0;
> > + code = (code + instr.displace) & 0xffff;
> > + return code == diag;
> > +}
>
> It looks like this transformation is equivalent for the PV case.

Yes, the PV case just has hardcoded values that we want to check.

> You
> could put the switch into the sie_is_pv() branch? Otherwise looks okay.

I want to validate diag for both PV and non PV.
>
> Reviewed-by: Nicholas Piggin <npiggin@gmail.com>

Thanks!