308 lines
8.7 KiB
C
308 lines
8.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* handling diagnose instructions
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*
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* Copyright IBM Corp. 2008, 2020
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*
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* Author(s): Carsten Otte <cotte@de.ibm.com>
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* Christian Borntraeger <borntraeger@de.ibm.com>
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*/
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#include <linux/kvm.h>
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#include <linux/kvm_host.h>
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#include <asm/gmap.h>
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#include <asm/virtio-ccw.h>
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#include "kvm-s390.h"
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#include "trace.h"
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#include "trace-s390.h"
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#include "gaccess.h"
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static int diag_release_pages(struct kvm_vcpu *vcpu)
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{
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unsigned long start, end;
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unsigned long prefix = kvm_s390_get_prefix(vcpu);
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start = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
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end = vcpu->run->s.regs.gprs[vcpu->arch.sie_block->ipa & 0xf] + PAGE_SIZE;
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vcpu->stat.instruction_diagnose_10++;
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if (start & ~PAGE_MASK || end & ~PAGE_MASK || start >= end
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|| start < 2 * PAGE_SIZE)
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return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
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VCPU_EVENT(vcpu, 5, "diag release pages %lX %lX", start, end);
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/*
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* We checked for start >= end above, so lets check for the
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* fast path (no prefix swap page involved)
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*/
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if (end <= prefix || start >= prefix + 2 * PAGE_SIZE) {
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gmap_discard(vcpu->arch.gmap, start, end);
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} else {
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/*
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* This is slow path. gmap_discard will check for start
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* so lets split this into before prefix, prefix, after
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* prefix and let gmap_discard make some of these calls
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* NOPs.
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*/
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gmap_discard(vcpu->arch.gmap, start, prefix);
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if (start <= prefix)
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gmap_discard(vcpu->arch.gmap, 0, PAGE_SIZE);
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if (end > prefix + PAGE_SIZE)
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gmap_discard(vcpu->arch.gmap, PAGE_SIZE, 2 * PAGE_SIZE);
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gmap_discard(vcpu->arch.gmap, prefix + 2 * PAGE_SIZE, end);
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}
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return 0;
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}
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static int __diag_page_ref_service(struct kvm_vcpu *vcpu)
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{
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struct prs_parm {
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u16 code;
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u16 subcode;
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u16 parm_len;
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u16 parm_version;
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u64 token_addr;
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u64 select_mask;
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u64 compare_mask;
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u64 zarch;
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};
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struct prs_parm parm;
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int rc;
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u16 rx = (vcpu->arch.sie_block->ipa & 0xf0) >> 4;
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u16 ry = (vcpu->arch.sie_block->ipa & 0x0f);
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VCPU_EVENT(vcpu, 3, "diag page reference parameter block at 0x%llx",
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vcpu->run->s.regs.gprs[rx]);
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vcpu->stat.instruction_diagnose_258++;
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if (vcpu->run->s.regs.gprs[rx] & 7)
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return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
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rc = read_guest(vcpu, vcpu->run->s.regs.gprs[rx], rx, &parm, sizeof(parm));
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if (rc)
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return kvm_s390_inject_prog_cond(vcpu, rc);
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if (parm.parm_version != 2 || parm.parm_len < 5 || parm.code != 0x258)
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return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
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switch (parm.subcode) {
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case 0: /* TOKEN */
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VCPU_EVENT(vcpu, 3, "pageref token addr 0x%llx "
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"select mask 0x%llx compare mask 0x%llx",
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parm.token_addr, parm.select_mask, parm.compare_mask);
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if (vcpu->arch.pfault_token != KVM_S390_PFAULT_TOKEN_INVALID) {
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/*
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* If the pagefault handshake is already activated,
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* the token must not be changed. We have to return
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* decimal 8 instead, as mandated in SC24-6084.
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*/
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vcpu->run->s.regs.gprs[ry] = 8;
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return 0;
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}
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if ((parm.compare_mask & parm.select_mask) != parm.compare_mask ||
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parm.token_addr & 7 || parm.zarch != 0x8000000000000000ULL)
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return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
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if (kvm_is_error_gpa(vcpu->kvm, parm.token_addr))
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return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
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vcpu->arch.pfault_token = parm.token_addr;
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vcpu->arch.pfault_select = parm.select_mask;
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vcpu->arch.pfault_compare = parm.compare_mask;
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vcpu->run->s.regs.gprs[ry] = 0;
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rc = 0;
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break;
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case 1: /*
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* CANCEL
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* Specification allows to let already pending tokens survive
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* the cancel, therefore to reduce code complexity, we assume
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* all outstanding tokens are already pending.
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*/
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VCPU_EVENT(vcpu, 3, "pageref cancel addr 0x%llx", parm.token_addr);
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if (parm.token_addr || parm.select_mask ||
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parm.compare_mask || parm.zarch)
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return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
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vcpu->run->s.regs.gprs[ry] = 0;
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/*
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* If the pfault handling was not established or is already
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* canceled SC24-6084 requests to return decimal 4.
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*/
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if (vcpu->arch.pfault_token == KVM_S390_PFAULT_TOKEN_INVALID)
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vcpu->run->s.regs.gprs[ry] = 4;
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else
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vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
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rc = 0;
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break;
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default:
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rc = -EOPNOTSUPP;
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break;
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}
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return rc;
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}
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static int __diag_time_slice_end(struct kvm_vcpu *vcpu)
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{
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VCPU_EVENT(vcpu, 5, "%s", "diag time slice end");
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vcpu->stat.instruction_diagnose_44++;
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kvm_vcpu_on_spin(vcpu, true);
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return 0;
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}
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static int forward_cnt;
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static unsigned long cur_slice;
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static int diag9c_forwarding_overrun(void)
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{
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/* Reset the count on a new slice */
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if (time_after(jiffies, cur_slice)) {
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cur_slice = jiffies;
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forward_cnt = diag9c_forwarding_hz / HZ;
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}
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return forward_cnt-- <= 0 ? 1 : 0;
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}
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static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu)
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{
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struct kvm_vcpu *tcpu;
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int tcpu_cpu;
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int tid;
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tid = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
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vcpu->stat.instruction_diagnose_9c++;
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/* yield to self */
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if (tid == vcpu->vcpu_id)
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goto no_yield;
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/* yield to invalid */
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tcpu = kvm_get_vcpu_by_id(vcpu->kvm, tid);
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if (!tcpu)
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goto no_yield;
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/* target guest VCPU already running */
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tcpu_cpu = READ_ONCE(tcpu->cpu);
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if (tcpu_cpu >= 0) {
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if (!diag9c_forwarding_hz || diag9c_forwarding_overrun())
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goto no_yield;
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/* target host CPU already running */
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if (!vcpu_is_preempted(tcpu_cpu))
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goto no_yield;
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smp_yield_cpu(tcpu_cpu);
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VCPU_EVENT(vcpu, 5,
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"diag time slice end directed to %d: yield forwarded",
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tid);
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vcpu->stat.diag_9c_forward++;
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return 0;
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}
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if (kvm_vcpu_yield_to(tcpu) <= 0)
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goto no_yield;
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VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d: done", tid);
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return 0;
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no_yield:
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VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d: ignored", tid);
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vcpu->stat.diag_9c_ignored++;
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return 0;
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}
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static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
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{
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unsigned int reg = vcpu->arch.sie_block->ipa & 0xf;
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unsigned long subcode = vcpu->run->s.regs.gprs[reg] & 0xffff;
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VCPU_EVENT(vcpu, 3, "diag ipl functions, subcode %lx", subcode);
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vcpu->stat.instruction_diagnose_308++;
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switch (subcode) {
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case 3:
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vcpu->run->s390_reset_flags = KVM_S390_RESET_CLEAR;
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break;
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case 4:
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vcpu->run->s390_reset_flags = 0;
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break;
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default:
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return -EOPNOTSUPP;
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}
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/*
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* no need to check the return value of vcpu_stop as it can only have
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* an error for protvirt, but protvirt means user cpu state
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*/
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if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))
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kvm_s390_vcpu_stop(vcpu);
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vcpu->run->s390_reset_flags |= KVM_S390_RESET_SUBSYSTEM;
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vcpu->run->s390_reset_flags |= KVM_S390_RESET_IPL;
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vcpu->run->s390_reset_flags |= KVM_S390_RESET_CPU_INIT;
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vcpu->run->exit_reason = KVM_EXIT_S390_RESET;
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VCPU_EVENT(vcpu, 3, "requesting userspace resets %llx",
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vcpu->run->s390_reset_flags);
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trace_kvm_s390_request_resets(vcpu->run->s390_reset_flags);
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return -EREMOTE;
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}
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static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
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{
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int ret;
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vcpu->stat.instruction_diagnose_500++;
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/* No virtio-ccw notification? Get out quickly. */
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if (!vcpu->kvm->arch.css_support ||
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(vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY))
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return -EOPNOTSUPP;
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VCPU_EVENT(vcpu, 4, "diag 0x500 schid 0x%8.8x queue 0x%x cookie 0x%llx",
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(u32) vcpu->run->s.regs.gprs[2],
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(u32) vcpu->run->s.regs.gprs[3],
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vcpu->run->s.regs.gprs[4]);
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/*
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* The layout is as follows:
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* - gpr 2 contains the subchannel id (passed as addr)
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* - gpr 3 contains the virtqueue index (passed as datamatch)
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* - gpr 4 contains the index on the bus (optionally)
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*/
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ret = kvm_io_bus_write_cookie(vcpu, KVM_VIRTIO_CCW_NOTIFY_BUS,
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vcpu->run->s.regs.gprs[2] & 0xffffffff,
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8, &vcpu->run->s.regs.gprs[3],
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vcpu->run->s.regs.gprs[4]);
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/*
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* Return cookie in gpr 2, but don't overwrite the register if the
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* diagnose will be handled by userspace.
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*/
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if (ret != -EOPNOTSUPP)
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vcpu->run->s.regs.gprs[2] = ret;
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/* kvm_io_bus_write_cookie returns -EOPNOTSUPP if it found no match. */
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return ret < 0 ? ret : 0;
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}
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int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)
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{
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int code = kvm_s390_get_base_disp_rs(vcpu, NULL) & 0xffff;
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if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
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return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
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trace_kvm_s390_handle_diag(vcpu, code);
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switch (code) {
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case 0x10:
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return diag_release_pages(vcpu);
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case 0x44:
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return __diag_time_slice_end(vcpu);
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case 0x9c:
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return __diag_time_slice_end_directed(vcpu);
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case 0x258:
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return __diag_page_ref_service(vcpu);
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case 0x308:
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return __diag_ipl_functions(vcpu);
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case 0x500:
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return __diag_virtio_hypercall(vcpu);
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default:
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vcpu->stat.instruction_diagnose_other++;
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return -EOPNOTSUPP;
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}
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}
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