blob: 7cb7799a0acb4000157554df8beec25634c6084b [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* Hosting Protected Virtual Machines
*
* Copyright IBM Corp. 2019, 2020
* Author(s): Janosch Frank <frankja@linux.ibm.com>
*/
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <linux/minmax.h>
#include <linux/pagemap.h>
#include <linux/sched/signal.h>
#include <asm/gmap.h>
#include <asm/uv.h>
#include <asm/mman.h>
#include <linux/pagewalk.h>
#include <linux/sched/mm.h>
#include <linux/mmu_notifier.h>
#include "kvm-s390.h"
static void kvm_s390_clear_pv_state(struct kvm *kvm)
{
kvm->arch.pv.handle = 0;
kvm->arch.pv.guest_len = 0;
kvm->arch.pv.stor_base = 0;
kvm->arch.pv.stor_var = NULL;
}
int kvm_s390_pv_destroy_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc)
{
int cc;
if (!kvm_s390_pv_cpu_get_handle(vcpu))
return 0;
cc = uv_cmd_nodata(kvm_s390_pv_cpu_get_handle(vcpu), UVC_CMD_DESTROY_SEC_CPU, rc, rrc);
KVM_UV_EVENT(vcpu->kvm, 3, "PROTVIRT DESTROY VCPU %d: rc %x rrc %x",
vcpu->vcpu_id, *rc, *rrc);
WARN_ONCE(cc, "protvirt destroy cpu failed rc %x rrc %x", *rc, *rrc);
/* Intended memory leak for something that should never happen. */
if (!cc)
free_pages(vcpu->arch.pv.stor_base,
get_order(uv_info.guest_cpu_stor_len));
free_page(sida_origin(vcpu->arch.sie_block));
vcpu->arch.sie_block->pv_handle_cpu = 0;
vcpu->arch.sie_block->pv_handle_config = 0;
memset(&vcpu->arch.pv, 0, sizeof(vcpu->arch.pv));
vcpu->arch.sie_block->sdf = 0;
/*
* The sidad field (for sdf == 2) is now the gbea field (for sdf == 0).
* Use the reset value of gbea to avoid leaking the kernel pointer of
* the just freed sida.
*/
vcpu->arch.sie_block->gbea = 1;
kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
return cc ? EIO : 0;
}
int kvm_s390_pv_create_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc)
{
struct uv_cb_csc uvcb = {
.header.cmd = UVC_CMD_CREATE_SEC_CPU,
.header.len = sizeof(uvcb),
};
int cc;
if (kvm_s390_pv_cpu_get_handle(vcpu))
return -EINVAL;
vcpu->arch.pv.stor_base = __get_free_pages(GFP_KERNEL_ACCOUNT,
get_order(uv_info.guest_cpu_stor_len));
if (!vcpu->arch.pv.stor_base)
return -ENOMEM;
/* Input */
uvcb.guest_handle = kvm_s390_pv_get_handle(vcpu->kvm);
uvcb.num = vcpu->arch.sie_block->icpua;
uvcb.state_origin = (u64)vcpu->arch.sie_block;
uvcb.stor_origin = (u64)vcpu->arch.pv.stor_base;
/* Alloc Secure Instruction Data Area Designation */
vcpu->arch.sie_block->sidad = __get_free_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
if (!vcpu->arch.sie_block->sidad) {
free_pages(vcpu->arch.pv.stor_base,
get_order(uv_info.guest_cpu_stor_len));
return -ENOMEM;
}
cc = uv_call(0, (u64)&uvcb);
*rc = uvcb.header.rc;
*rrc = uvcb.header.rrc;
KVM_UV_EVENT(vcpu->kvm, 3,
"PROTVIRT CREATE VCPU: cpu %d handle %llx rc %x rrc %x",
vcpu->vcpu_id, uvcb.cpu_handle, uvcb.header.rc,
uvcb.header.rrc);
if (cc) {
u16 dummy;
kvm_s390_pv_destroy_cpu(vcpu, &dummy, &dummy);
return -EIO;
}
/* Output */
vcpu->arch.pv.handle = uvcb.cpu_handle;
vcpu->arch.sie_block->pv_handle_cpu = uvcb.cpu_handle;
vcpu->arch.sie_block->pv_handle_config = kvm_s390_pv_get_handle(vcpu->kvm);
vcpu->arch.sie_block->sdf = 2;
kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
return 0;
}
/* only free resources when the destroy was successful */
static void kvm_s390_pv_dealloc_vm(struct kvm *kvm)
{
vfree(kvm->arch.pv.stor_var);
free_pages(kvm->arch.pv.stor_base,
get_order(uv_info.guest_base_stor_len));
kvm_s390_clear_pv_state(kvm);
}
static int kvm_s390_pv_alloc_vm(struct kvm *kvm)
{
unsigned long base = uv_info.guest_base_stor_len;
unsigned long virt = uv_info.guest_virt_var_stor_len;
unsigned long npages = 0, vlen = 0;
kvm->arch.pv.stor_var = NULL;
kvm->arch.pv.stor_base = __get_free_pages(GFP_KERNEL_ACCOUNT, get_order(base));
if (!kvm->arch.pv.stor_base)
return -ENOMEM;
/*
* Calculate current guest storage for allocation of the
* variable storage, which is based on the length in MB.
*
* Slots are sorted by GFN
*/
mutex_lock(&kvm->slots_lock);
npages = kvm_s390_get_gfn_end(kvm_memslots(kvm));
mutex_unlock(&kvm->slots_lock);
kvm->arch.pv.guest_len = npages * PAGE_SIZE;
/* Allocate variable storage */
vlen = ALIGN(virt * ((npages * PAGE_SIZE) / HPAGE_SIZE), PAGE_SIZE);
vlen += uv_info.guest_virt_base_stor_len;
kvm->arch.pv.stor_var = vzalloc(vlen);
if (!kvm->arch.pv.stor_var)
goto out_err;
return 0;
out_err:
kvm_s390_pv_dealloc_vm(kvm);
return -ENOMEM;
}
/* this should not fail, but if it does, we must not free the donated memory */
int kvm_s390_pv_deinit_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
{
int cc;
cc = uv_cmd_nodata(kvm_s390_pv_get_handle(kvm),
UVC_CMD_DESTROY_SEC_CONF, rc, rrc);
WRITE_ONCE(kvm->arch.gmap->guest_handle, 0);
/*
* if the mm still has a mapping, make all its pages accessible
* before destroying the guest
*/
if (mmget_not_zero(kvm->mm)) {
s390_uv_destroy_range(kvm->mm, 0, TASK_SIZE);
mmput(kvm->mm);
}
if (!cc) {
atomic_dec(&kvm->mm->context.protected_count);
kvm_s390_pv_dealloc_vm(kvm);
} else {
/* Intended memory leak on "impossible" error */
s390_replace_asce(kvm->arch.gmap);
}
KVM_UV_EVENT(kvm, 3, "PROTVIRT DESTROY VM: rc %x rrc %x", *rc, *rrc);
WARN_ONCE(cc, "protvirt destroy vm failed rc %x rrc %x", *rc, *rrc);
return cc ? -EIO : 0;
}
static void kvm_s390_pv_mmu_notifier_release(struct mmu_notifier *subscription,
struct mm_struct *mm)
{
struct kvm *kvm = container_of(subscription, struct kvm, arch.pv.mmu_notifier);
u16 dummy;
/*
* No locking is needed since this is the last thread of the last user of this
* struct mm.
* When the struct kvm gets deinitialized, this notifier is also
* unregistered. This means that if this notifier runs, then the
* struct kvm is still valid.
*/
kvm_s390_cpus_from_pv(kvm, &dummy, &dummy);
}
static const struct mmu_notifier_ops kvm_s390_pv_mmu_notifier_ops = {
.release = kvm_s390_pv_mmu_notifier_release,
};
int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
{
struct uv_cb_cgc uvcb = {
.header.cmd = UVC_CMD_CREATE_SEC_CONF,
.header.len = sizeof(uvcb)
};
int cc, ret;
u16 dummy;
ret = kvm_s390_pv_alloc_vm(kvm);
if (ret)
return ret;
/* Inputs */
uvcb.guest_stor_origin = 0; /* MSO is 0 for KVM */
uvcb.guest_stor_len = kvm->arch.pv.guest_len;
uvcb.guest_asce = kvm->arch.gmap->asce;
uvcb.guest_sca = (unsigned long)kvm->arch.sca;
uvcb.conf_base_stor_origin = (u64)kvm->arch.pv.stor_base;
uvcb.conf_virt_stor_origin = (u64)kvm->arch.pv.stor_var;
cc = uv_call_sched(0, (u64)&uvcb);
*rc = uvcb.header.rc;
*rrc = uvcb.header.rrc;
KVM_UV_EVENT(kvm, 3, "PROTVIRT CREATE VM: handle %llx len %llx rc %x rrc %x",
uvcb.guest_handle, uvcb.guest_stor_len, *rc, *rrc);
/* Outputs */
kvm->arch.pv.handle = uvcb.guest_handle;
atomic_inc(&kvm->mm->context.protected_count);
if (cc) {
if (uvcb.header.rc & UVC_RC_NEED_DESTROY) {
kvm_s390_pv_deinit_vm(kvm, &dummy, &dummy);
} else {
atomic_dec(&kvm->mm->context.protected_count);
kvm_s390_pv_dealloc_vm(kvm);
}
return -EIO;
}
kvm->arch.gmap->guest_handle = uvcb.guest_handle;
/* Add the notifier only once. No races because we hold kvm->lock */
if (kvm->arch.pv.mmu_notifier.ops != &kvm_s390_pv_mmu_notifier_ops) {
kvm->arch.pv.mmu_notifier.ops = &kvm_s390_pv_mmu_notifier_ops;
mmu_notifier_register(&kvm->arch.pv.mmu_notifier, kvm->mm);
}
return 0;
}
int kvm_s390_pv_set_sec_parms(struct kvm *kvm, void *hdr, u64 length, u16 *rc,
u16 *rrc)
{
struct uv_cb_ssc uvcb = {
.header.cmd = UVC_CMD_SET_SEC_CONF_PARAMS,
.header.len = sizeof(uvcb),
.sec_header_origin = (u64)hdr,
.sec_header_len = length,
.guest_handle = kvm_s390_pv_get_handle(kvm),
};
int cc = uv_call(0, (u64)&uvcb);
*rc = uvcb.header.rc;
*rrc = uvcb.header.rrc;
KVM_UV_EVENT(kvm, 3, "PROTVIRT VM SET PARMS: rc %x rrc %x",
*rc, *rrc);
return cc ? -EINVAL : 0;
}
static int unpack_one(struct kvm *kvm, unsigned long addr, u64 tweak,
u64 offset, u16 *rc, u16 *rrc)
{
struct uv_cb_unp uvcb = {
.header.cmd = UVC_CMD_UNPACK_IMG,
.header.len = sizeof(uvcb),
.guest_handle = kvm_s390_pv_get_handle(kvm),
.gaddr = addr,
.tweak[0] = tweak,
.tweak[1] = offset,
};
int ret = gmap_make_secure(kvm->arch.gmap, addr, &uvcb);
*rc = uvcb.header.rc;
*rrc = uvcb.header.rrc;
if (ret && ret != -EAGAIN)
KVM_UV_EVENT(kvm, 3, "PROTVIRT VM UNPACK: failed addr %llx with rc %x rrc %x",
uvcb.gaddr, *rc, *rrc);
return ret;
}
int kvm_s390_pv_unpack(struct kvm *kvm, unsigned long addr, unsigned long size,
unsigned long tweak, u16 *rc, u16 *rrc)
{
u64 offset = 0;
int ret = 0;
if (addr & ~PAGE_MASK || !size || size & ~PAGE_MASK)
return -EINVAL;
KVM_UV_EVENT(kvm, 3, "PROTVIRT VM UNPACK: start addr %lx size %lx",
addr, size);
while (offset < size) {
ret = unpack_one(kvm, addr, tweak, offset, rc, rrc);
if (ret == -EAGAIN) {
cond_resched();
if (fatal_signal_pending(current))
break;
continue;
}
if (ret)
break;
addr += PAGE_SIZE;
offset += PAGE_SIZE;
}
if (!ret)
KVM_UV_EVENT(kvm, 3, "%s", "PROTVIRT VM UNPACK: successful");
return ret;
}
int kvm_s390_pv_set_cpu_state(struct kvm_vcpu *vcpu, u8 state)
{
struct uv_cb_cpu_set_state uvcb = {
.header.cmd = UVC_CMD_CPU_SET_STATE,
.header.len = sizeof(uvcb),
.cpu_handle = kvm_s390_pv_cpu_get_handle(vcpu),
.state = state,
};
int cc;
cc = uv_call(0, (u64)&uvcb);
KVM_UV_EVENT(vcpu->kvm, 3, "PROTVIRT SET CPU %d STATE %d rc %x rrc %x",
vcpu->vcpu_id, state, uvcb.header.rc, uvcb.header.rrc);
if (cc)
return -EINVAL;
return 0;
}
int kvm_s390_pv_dump_cpu(struct kvm_vcpu *vcpu, void *buff, u16 *rc, u16 *rrc)
{
struct uv_cb_dump_cpu uvcb = {
.header.cmd = UVC_CMD_DUMP_CPU,
.header.len = sizeof(uvcb),
.cpu_handle = vcpu->arch.pv.handle,
.dump_area_origin = (u64)buff,
};
int cc;
cc = uv_call_sched(0, (u64)&uvcb);
*rc = uvcb.header.rc;
*rrc = uvcb.header.rrc;
return cc;
}
/* Size of the cache for the storage state dump data. 1MB for now */
#define DUMP_BUFF_LEN HPAGE_SIZE
/**
* kvm_s390_pv_dump_stor_state
*
* @kvm: pointer to the guest's KVM struct
* @buff_user: Userspace pointer where we will write the results to
* @gaddr: Starting absolute guest address for which the storage state
* is requested.
* @buff_user_len: Length of the buff_user buffer
* @rc: Pointer to where the uvcb return code is stored
* @rrc: Pointer to where the uvcb return reason code is stored
*
* Stores buff_len bytes of tweak component values to buff_user
* starting with the 1MB block specified by the absolute guest address
* (gaddr). The gaddr pointer will be updated with the last address
* for which data was written when returning to userspace. buff_user
* might be written to even if an error rc is returned. For instance
* if we encounter a fault after writing the first page of data.
*
* Context: kvm->lock needs to be held
*
* Return:
* 0 on success
* -ENOMEM if allocating the cache fails
* -EINVAL if gaddr is not aligned to 1MB
* -EINVAL if buff_user_len is not aligned to uv_info.conf_dump_storage_state_len
* -EINVAL if the UV call fails, rc and rrc will be set in this case
* -EFAULT if copying the result to buff_user failed
*/
int kvm_s390_pv_dump_stor_state(struct kvm *kvm, void __user *buff_user,
u64 *gaddr, u64 buff_user_len, u16 *rc, u16 *rrc)
{
struct uv_cb_dump_stor_state uvcb = {
.header.cmd = UVC_CMD_DUMP_CONF_STOR_STATE,
.header.len = sizeof(uvcb),
.config_handle = kvm->arch.pv.handle,
.gaddr = *gaddr,
.dump_area_origin = 0,
};
const u64 increment_len = uv_info.conf_dump_storage_state_len;
size_t buff_kvm_size;
size_t size_done = 0;
u8 *buff_kvm = NULL;
int cc, ret;
ret = -EINVAL;
/* UV call processes 1MB guest storage chunks at a time */
if (!IS_ALIGNED(*gaddr, HPAGE_SIZE))
goto out;
/*
* We provide the storage state for 1MB chunks of guest
* storage. The buffer will need to be aligned to
* conf_dump_storage_state_len so we don't end on a partial
* chunk.
*/
if (!buff_user_len ||
!IS_ALIGNED(buff_user_len, increment_len))
goto out;
/*
* Allocate a buffer from which we will later copy to the user
* process. We don't want userspace to dictate our buffer size
* so we limit it to DUMP_BUFF_LEN.
*/
ret = -ENOMEM;
buff_kvm_size = min_t(u64, buff_user_len, DUMP_BUFF_LEN);
buff_kvm = vzalloc(buff_kvm_size);
if (!buff_kvm)
goto out;
ret = 0;
uvcb.dump_area_origin = (u64)buff_kvm;
/* We will loop until the user buffer is filled or an error occurs */
do {
/* Get 1MB worth of guest storage state data */
cc = uv_call_sched(0, (u64)&uvcb);
/* All or nothing */
if (cc) {
ret = -EINVAL;
break;
}
size_done += increment_len;
uvcb.dump_area_origin += increment_len;
buff_user_len -= increment_len;
uvcb.gaddr += HPAGE_SIZE;
/* KVM Buffer full, time to copy to the process */
if (!buff_user_len || size_done == DUMP_BUFF_LEN) {
if (copy_to_user(buff_user, buff_kvm, size_done)) {
ret = -EFAULT;
break;
}
buff_user += size_done;
size_done = 0;
uvcb.dump_area_origin = (u64)buff_kvm;
}
} while (buff_user_len);
/* Report back where we ended dumping */
*gaddr = uvcb.gaddr;
/* Lets only log errors, we don't want to spam */
out:
if (ret)
KVM_UV_EVENT(kvm, 3,
"PROTVIRT DUMP STORAGE STATE: addr %llx ret %d, uvcb rc %x rrc %x",
uvcb.gaddr, ret, uvcb.header.rc, uvcb.header.rrc);
*rc = uvcb.header.rc;
*rrc = uvcb.header.rrc;
vfree(buff_kvm);
return ret;
}
/**
* kvm_s390_pv_dump_complete
*
* @kvm: pointer to the guest's KVM struct
* @buff_user: Userspace pointer where we will write the results to
* @rc: Pointer to where the uvcb return code is stored
* @rrc: Pointer to where the uvcb return reason code is stored
*
* Completes the dumping operation and writes the completion data to
* user space.
*
* Context: kvm->lock needs to be held
*
* Return:
* 0 on success
* -ENOMEM if allocating the completion buffer fails
* -EINVAL if the UV call fails, rc and rrc will be set in this case
* -EFAULT if copying the result to buff_user failed
*/
int kvm_s390_pv_dump_complete(struct kvm *kvm, void __user *buff_user,
u16 *rc, u16 *rrc)
{
struct uv_cb_dump_complete complete = {
.header.len = sizeof(complete),
.header.cmd = UVC_CMD_DUMP_COMPLETE,
.config_handle = kvm_s390_pv_get_handle(kvm),
};
u64 *compl_data;
int ret;
/* Allocate dump area */
compl_data = vzalloc(uv_info.conf_dump_finalize_len);
if (!compl_data)
return -ENOMEM;
complete.dump_area_origin = (u64)compl_data;
ret = uv_call_sched(0, (u64)&complete);
*rc = complete.header.rc;
*rrc = complete.header.rrc;
KVM_UV_EVENT(kvm, 3, "PROTVIRT DUMP COMPLETE: rc %x rrc %x",
complete.header.rc, complete.header.rrc);
if (!ret) {
/*
* kvm_s390_pv_dealloc_vm() will also (mem)set
* this to false on a reboot or other destroy
* operation for this vm.
*/
kvm->arch.pv.dumping = false;
kvm_s390_vcpu_unblock_all(kvm);
ret = copy_to_user(buff_user, compl_data, uv_info.conf_dump_finalize_len);
if (ret)
ret = -EFAULT;
}
vfree(compl_data);
/* If the UVC returned an error, translate it to -EINVAL */
if (ret > 0)
ret = -EINVAL;
return ret;
}