Correctly handle the MVPG instruction when issued by a VSIE guest.

Fixes: a3508fbe9dc6d ("KVM: s390: vsie: initial support for nested virtualization") Cc: stable@vger.kernel.org Signed-off-by: Claudio Imbrenda imbrenda@linux.ibm.com Acked-by: Janosch Frank frankja@linux.ibm.com Reviewed-by: David Hildenbrand david@redhat.com --- arch/s390/kvm/vsie.c | 98 +++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 93 insertions(+), 5 deletions(-)

diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c index 78b604326016..48aab6290a77 100644 --- a/arch/s390/kvm/vsie.c +++ b/arch/s390/kvm/vsie.c @@ -417,11 +417,6 @@ static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) memcpy((void *)((u64)scb_o + 0xc0), (void *)((u64)scb_s + 0xc0), 0xf0 - 0xc0); break; - case ICPT_PARTEXEC: - /* MVPG only */ - memcpy((void *)((u64)scb_o + 0xc0), - (void *)((u64)scb_s + 0xc0), 0xd0 - 0xc0); - break; }

if (scb_s->ihcpu != 0xffffU) @@ -983,6 +978,95 @@ static int handle_stfle(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) return 0; }

+/* + * Get a register for a nested guest. + * @vcpu the vcpu of the guest + * @vsie_page the vsie_page for the nested guest + * @reg the register number, the upper 4 bits are ignored. + * returns: the value of the register. + */ +static u64 vsie_get_register(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, u8 reg) +{ + /* no need to validate the parameter and/or perform error handling */ + reg &= 0xf; + switch (reg) { + case 15: + return vsie_page->scb_s.gg15; + case 14: + return vsie_page->scb_s.gg14; + default: + return vcpu->run->s.regs.gprs[reg]; + } +} + +static int vsie_handle_mvpg(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) +{ + struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; + unsigned long pei_dest, pei_src, src, dest, mask; + u64 *pei_block = &vsie_page->scb_o->mcic; + int edat, rc_dest, rc_src; + union ctlreg0 cr0; + + cr0.val = vcpu->arch.sie_block->gcr[0]; + edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8); + mask = _kvm_s390_logical_to_effective(&scb_s->gpsw, PAGE_MASK); + + dest = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 16) & mask; + src = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 20) & mask; + + rc_dest = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, dest, &pei_dest); + rc_src = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, src, &pei_src); + /* + * Either everything went well, or something non-critical went wrong + * e.g. because of a race. In either case, simply retry. + */ + if (rc_dest == -EAGAIN || rc_src == -EAGAIN || (!rc_dest && !rc_src)) { + retry_vsie_icpt(vsie_page); + return -EAGAIN; + } + /* Something more serious went wrong, propagate the error */ + if (rc_dest < 0) + return rc_dest; + if (rc_src < 0) + return rc_src; + + /* The only possible suppressing exception: just deliver it */ + if (rc_dest == PGM_TRANSLATION_SPEC || rc_src == PGM_TRANSLATION_SPEC) { + clear_vsie_icpt(vsie_page); + rc_dest = kvm_s390_inject_program_int(vcpu, PGM_TRANSLATION_SPEC); + WARN_ON_ONCE(rc_dest); + return 1; + } + + /* + * Forward the PEI intercept to the guest if it was a page fault, or + * also for segment and region table faults if EDAT applies. + */ + if (edat) { + rc_dest = rc_dest == PGM_ASCE_TYPE ? rc_dest : 0; + rc_src = rc_src == PGM_ASCE_TYPE ? rc_src : 0; + } else { + rc_dest = rc_dest != PGM_PAGE_TRANSLATION ? rc_dest : 0; + rc_src = rc_src != PGM_PAGE_TRANSLATION ? rc_src : 0; + } + if (!rc_dest && !rc_src) { + pei_block[0] = pei_dest; + pei_block[1] = pei_src; + return 1; + } + + retry_vsie_icpt(vsie_page); + + /* + * The host has edat, and the guest does not, or it was an ASCE type + * exception. The host needs to inject the appropriate DAT interrupts + * into the guest. + */ + if (rc_dest) + return inject_fault(vcpu, rc_dest, dest, 1); + return inject_fault(vcpu, rc_src, src, 0); +} + /* * Run the vsie on a shadow scb and a shadow gmap, without any further * sanity checks, handling SIE faults. @@ -1071,6 +1155,10 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) if ((scb_s->ipa & 0xf000) != 0xf000) scb_s->ipa += 0x1000; break; + case ICPT_PARTEXEC: + if (scb_s->ipa == 0xb254) + rc = vsie_handle_mvpg(vcpu, vsie_page); + break; } return rc; }