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