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linux/arch/s390/kvm/diag.c
Christian Borntraeger f7a960affc KVM: s390/cmm: Fix prefix handling for diag 10 balloon 
The old handling of prefix pages was broken in the diag10 ballooner.
We now rely on gmap_discard to check for start > end and do a
slow path if the prefix swap pages are affected:
1. discard the pages from start to prefix
2. discard the absolute 0 pages
3. discard the pages after prefix swap to end

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
2014-09-10 12:19:42 +02:00

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/*
* handling diagnose instructions
*
* Copyright IBM Corp. 2008, 2011
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License (version 2 only)
* as published by the Free Software Foundation.
*
* 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/pgalloc.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] + 4096;
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);
vcpu->stat.diagnose_10++;
/*
* 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, 4096);
if (end > prefix + 4096)
gmap_discard(vcpu->arch.gmap, 4096, 8192);
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);
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], &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 */
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.
*/
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.diagnose_44++;
kvm_vcpu_on_spin(vcpu);
return 0;
}
static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu)
{
struct kvm *kvm = vcpu->kvm;
struct kvm_vcpu *tcpu;
int tid;
int i;
tid = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
vcpu->stat.diagnose_9c++;
VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d", tid);
if (tid == vcpu->vcpu_id)
return 0;
kvm_for_each_vcpu(i, tcpu, kvm)
if (tcpu->vcpu_id == tid) {
kvm_vcpu_yield_to(tcpu);
break;
}
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, 5, "diag ipl functions, subcode %lx", subcode);
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;
}
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;
/* 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;
/*
* 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, 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) & 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:
return -EOPNOTSUPP;
}
}
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