linux/arch/powerpc/kvm/powerpc.c
Paul Mackerras 19ccb76a19 KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code
With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per
core), whenever a CPU goes idle, we have to pull all the other
hardware threads in the core out of the guest, because the H_CEDE
hcall is handled in the kernel.  This is inefficient.

This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall
in real mode.  When a guest vcpu does an H_CEDE hcall, we now only
exit to the kernel if all the other vcpus in the same core are also
idle.  Otherwise we mark this vcpu as napping, save state that could
be lost in nap mode (mainly GPRs and FPRs), and execute the nap
instruction.  When the thread wakes up, because of a decrementer or
external interrupt, we come back in at kvm_start_guest (from the
system reset interrupt vector), find the `napping' flag set in the
paca, and go to the resume path.

This has some other ramifications.  First, when starting a core, we
now start all the threads, both those that are immediately runnable and
those that are idle.  This is so that we don't have to pull all the
threads out of the guest when an idle thread gets a decrementer interrupt
and wants to start running.  In fact the idle threads will all start
with the H_CEDE hcall returning; being idle they will just do another
H_CEDE immediately and go to nap mode.

This required some changes to kvmppc_run_core() and kvmppc_run_vcpu().
These functions have been restructured to make them simpler and clearer.
We introduce a level of indirection in the wait queue that gets woken
when external and decrementer interrupts get generated for a vcpu, so
that we can have the 4 vcpus in a vcore using the same wait queue.
We need this because the 4 vcpus are being handled by one thread.

Secondly, when we need to exit from the guest to the kernel, we now
have to generate an IPI for any napping threads, because an HDEC
interrupt doesn't wake up a napping thread.

Thirdly, we now need to be able to handle virtual external interrupts
and decrementer interrupts becoming pending while a thread is napping,
and deliver those interrupts to the guest when the thread wakes.
This is done in kvmppc_cede_reentry, just before fast_guest_return.

Finally, since we are not using the generic kvm_vcpu_block for book3s_hv,
and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef
from kvm_arch_vcpu_runnable.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
2011-09-25 19:52:30 +03:00

742 lines
16 KiB
C

/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* Copyright IBM Corp. 2007
*
* Authors: Hollis Blanchard <hollisb@us.ibm.com>
* Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
*/
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kvm_host.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/hrtimer.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <asm/cputable.h>
#include <asm/uaccess.h>
#include <asm/kvm_ppc.h>
#include <asm/tlbflush.h>
#include <asm/cputhreads.h>
#include "timing.h"
#include "../mm/mmu_decl.h"
#define CREATE_TRACE_POINTS
#include "trace.h"
int kvm_arch_vcpu_runnable(struct kvm_vcpu *v)
{
return !(v->arch.shared->msr & MSR_WE) ||
!!(v->arch.pending_exceptions);
}
int kvmppc_kvm_pv(struct kvm_vcpu *vcpu)
{
int nr = kvmppc_get_gpr(vcpu, 11);
int r;
unsigned long __maybe_unused param1 = kvmppc_get_gpr(vcpu, 3);
unsigned long __maybe_unused param2 = kvmppc_get_gpr(vcpu, 4);
unsigned long __maybe_unused param3 = kvmppc_get_gpr(vcpu, 5);
unsigned long __maybe_unused param4 = kvmppc_get_gpr(vcpu, 6);
unsigned long r2 = 0;
if (!(vcpu->arch.shared->msr & MSR_SF)) {
/* 32 bit mode */
param1 &= 0xffffffff;
param2 &= 0xffffffff;
param3 &= 0xffffffff;
param4 &= 0xffffffff;
}
switch (nr) {
case HC_VENDOR_KVM | KVM_HC_PPC_MAP_MAGIC_PAGE:
{
vcpu->arch.magic_page_pa = param1;
vcpu->arch.magic_page_ea = param2;
r2 = KVM_MAGIC_FEAT_SR;
r = HC_EV_SUCCESS;
break;
}
case HC_VENDOR_KVM | KVM_HC_FEATURES:
r = HC_EV_SUCCESS;
#if defined(CONFIG_PPC_BOOK3S) || defined(CONFIG_KVM_E500)
/* XXX Missing magic page on 44x */
r2 |= (1 << KVM_FEATURE_MAGIC_PAGE);
#endif
/* Second return value is in r4 */
break;
default:
r = HC_EV_UNIMPLEMENTED;
break;
}
kvmppc_set_gpr(vcpu, 4, r2);
return r;
}
int kvmppc_sanity_check(struct kvm_vcpu *vcpu)
{
int r = false;
/* We have to know what CPU to virtualize */
if (!vcpu->arch.pvr)
goto out;
/* PAPR only works with book3s_64 */
if ((vcpu->arch.cpu_type != KVM_CPU_3S_64) && vcpu->arch.papr_enabled)
goto out;
#ifdef CONFIG_KVM_BOOK3S_64_HV
/* HV KVM can only do PAPR mode for now */
if (!vcpu->arch.papr_enabled)
goto out;
#endif
r = true;
out:
vcpu->arch.sane = r;
return r ? 0 : -EINVAL;
}
int kvmppc_emulate_mmio(struct kvm_run *run, struct kvm_vcpu *vcpu)
{
enum emulation_result er;
int r;
er = kvmppc_emulate_instruction(run, vcpu);
switch (er) {
case EMULATE_DONE:
/* Future optimization: only reload non-volatiles if they were
* actually modified. */
r = RESUME_GUEST_NV;
break;
case EMULATE_DO_MMIO:
run->exit_reason = KVM_EXIT_MMIO;
/* We must reload nonvolatiles because "update" load/store
* instructions modify register state. */
/* Future optimization: only reload non-volatiles if they were
* actually modified. */
r = RESUME_HOST_NV;
break;
case EMULATE_FAIL:
/* XXX Deliver Program interrupt to guest. */
printk(KERN_EMERG "%s: emulation failed (%08x)\n", __func__,
kvmppc_get_last_inst(vcpu));
r = RESUME_HOST;
break;
default:
BUG();
}
return r;
}
int kvm_arch_hardware_enable(void *garbage)
{
return 0;
}
void kvm_arch_hardware_disable(void *garbage)
{
}
int kvm_arch_hardware_setup(void)
{
return 0;
}
void kvm_arch_hardware_unsetup(void)
{
}
void kvm_arch_check_processor_compat(void *rtn)
{
*(int *)rtn = kvmppc_core_check_processor_compat();
}
int kvm_arch_init_vm(struct kvm *kvm)
{
return kvmppc_core_init_vm(kvm);
}
void kvm_arch_destroy_vm(struct kvm *kvm)
{
unsigned int i;
struct kvm_vcpu *vcpu;
kvm_for_each_vcpu(i, vcpu, kvm)
kvm_arch_vcpu_free(vcpu);
mutex_lock(&kvm->lock);
for (i = 0; i < atomic_read(&kvm->online_vcpus); i++)
kvm->vcpus[i] = NULL;
atomic_set(&kvm->online_vcpus, 0);
kvmppc_core_destroy_vm(kvm);
mutex_unlock(&kvm->lock);
}
void kvm_arch_sync_events(struct kvm *kvm)
{
}
int kvm_dev_ioctl_check_extension(long ext)
{
int r;
switch (ext) {
#ifdef CONFIG_BOOKE
case KVM_CAP_PPC_BOOKE_SREGS:
#else
case KVM_CAP_PPC_SEGSTATE:
case KVM_CAP_PPC_HIOR:
case KVM_CAP_PPC_PAPR:
#endif
case KVM_CAP_PPC_UNSET_IRQ:
case KVM_CAP_PPC_IRQ_LEVEL:
case KVM_CAP_ENABLE_CAP:
r = 1;
break;
#ifndef CONFIG_KVM_BOOK3S_64_HV
case KVM_CAP_PPC_PAIRED_SINGLES:
case KVM_CAP_PPC_OSI:
case KVM_CAP_PPC_GET_PVINFO:
r = 1;
break;
case KVM_CAP_COALESCED_MMIO:
r = KVM_COALESCED_MMIO_PAGE_OFFSET;
break;
#endif
#ifdef CONFIG_KVM_BOOK3S_64_HV
case KVM_CAP_SPAPR_TCE:
r = 1;
break;
case KVM_CAP_PPC_SMT:
r = threads_per_core;
break;
case KVM_CAP_PPC_RMA:
r = 1;
/* PPC970 requires an RMA */
if (cpu_has_feature(CPU_FTR_ARCH_201))
r = 2;
break;
#endif
default:
r = 0;
break;
}
return r;
}
long kvm_arch_dev_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
return -EINVAL;
}
int kvm_arch_prepare_memory_region(struct kvm *kvm,
struct kvm_memory_slot *memslot,
struct kvm_memory_slot old,
struct kvm_userspace_memory_region *mem,
int user_alloc)
{
return kvmppc_core_prepare_memory_region(kvm, mem);
}
void kvm_arch_commit_memory_region(struct kvm *kvm,
struct kvm_userspace_memory_region *mem,
struct kvm_memory_slot old,
int user_alloc)
{
kvmppc_core_commit_memory_region(kvm, mem);
}
void kvm_arch_flush_shadow(struct kvm *kvm)
{
}
struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
{
struct kvm_vcpu *vcpu;
vcpu = kvmppc_core_vcpu_create(kvm, id);
vcpu->arch.wqp = &vcpu->wq;
if (!IS_ERR(vcpu))
kvmppc_create_vcpu_debugfs(vcpu, id);
return vcpu;
}
void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
{
/* Make sure we're not using the vcpu anymore */
hrtimer_cancel(&vcpu->arch.dec_timer);
tasklet_kill(&vcpu->arch.tasklet);
kvmppc_remove_vcpu_debugfs(vcpu);
kvmppc_core_vcpu_free(vcpu);
}
void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
{
kvm_arch_vcpu_free(vcpu);
}
int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
{
return kvmppc_core_pending_dec(vcpu);
}
static void kvmppc_decrementer_func(unsigned long data)
{
struct kvm_vcpu *vcpu = (struct kvm_vcpu *)data;
kvmppc_core_queue_dec(vcpu);
if (waitqueue_active(vcpu->arch.wqp)) {
wake_up_interruptible(vcpu->arch.wqp);
vcpu->stat.halt_wakeup++;
}
}
/*
* low level hrtimer wake routine. Because this runs in hardirq context
* we schedule a tasklet to do the real work.
*/
enum hrtimer_restart kvmppc_decrementer_wakeup(struct hrtimer *timer)
{
struct kvm_vcpu *vcpu;
vcpu = container_of(timer, struct kvm_vcpu, arch.dec_timer);
tasklet_schedule(&vcpu->arch.tasklet);
return HRTIMER_NORESTART;
}
int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
{
hrtimer_init(&vcpu->arch.dec_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
tasklet_init(&vcpu->arch.tasklet, kvmppc_decrementer_func, (ulong)vcpu);
vcpu->arch.dec_timer.function = kvmppc_decrementer_wakeup;
vcpu->arch.dec_expires = ~(u64)0;
#ifdef CONFIG_KVM_EXIT_TIMING
mutex_init(&vcpu->arch.exit_timing_lock);
#endif
return 0;
}
void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
{
kvmppc_mmu_destroy(vcpu);
}
void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
#ifdef CONFIG_BOOKE
/*
* vrsave (formerly usprg0) isn't used by Linux, but may
* be used by the guest.
*
* On non-booke this is associated with Altivec and
* is handled by code in book3s.c.
*/
mtspr(SPRN_VRSAVE, vcpu->arch.vrsave);
#endif
kvmppc_core_vcpu_load(vcpu, cpu);
vcpu->cpu = smp_processor_id();
}
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
{
kvmppc_core_vcpu_put(vcpu);
#ifdef CONFIG_BOOKE
vcpu->arch.vrsave = mfspr(SPRN_VRSAVE);
#endif
vcpu->cpu = -1;
}
int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
struct kvm_guest_debug *dbg)
{
return -EINVAL;
}
static void kvmppc_complete_dcr_load(struct kvm_vcpu *vcpu,
struct kvm_run *run)
{
kvmppc_set_gpr(vcpu, vcpu->arch.io_gpr, run->dcr.data);
}
static void kvmppc_complete_mmio_load(struct kvm_vcpu *vcpu,
struct kvm_run *run)
{
u64 uninitialized_var(gpr);
if (run->mmio.len > sizeof(gpr)) {
printk(KERN_ERR "bad MMIO length: %d\n", run->mmio.len);
return;
}
if (vcpu->arch.mmio_is_bigendian) {
switch (run->mmio.len) {
case 8: gpr = *(u64 *)run->mmio.data; break;
case 4: gpr = *(u32 *)run->mmio.data; break;
case 2: gpr = *(u16 *)run->mmio.data; break;
case 1: gpr = *(u8 *)run->mmio.data; break;
}
} else {
/* Convert BE data from userland back to LE. */
switch (run->mmio.len) {
case 4: gpr = ld_le32((u32 *)run->mmio.data); break;
case 2: gpr = ld_le16((u16 *)run->mmio.data); break;
case 1: gpr = *(u8 *)run->mmio.data; break;
}
}
if (vcpu->arch.mmio_sign_extend) {
switch (run->mmio.len) {
#ifdef CONFIG_PPC64
case 4:
gpr = (s64)(s32)gpr;
break;
#endif
case 2:
gpr = (s64)(s16)gpr;
break;
case 1:
gpr = (s64)(s8)gpr;
break;
}
}
kvmppc_set_gpr(vcpu, vcpu->arch.io_gpr, gpr);
switch (vcpu->arch.io_gpr & KVM_REG_EXT_MASK) {
case KVM_REG_GPR:
kvmppc_set_gpr(vcpu, vcpu->arch.io_gpr, gpr);
break;
case KVM_REG_FPR:
vcpu->arch.fpr[vcpu->arch.io_gpr & KVM_REG_MASK] = gpr;
break;
#ifdef CONFIG_PPC_BOOK3S
case KVM_REG_QPR:
vcpu->arch.qpr[vcpu->arch.io_gpr & KVM_REG_MASK] = gpr;
break;
case KVM_REG_FQPR:
vcpu->arch.fpr[vcpu->arch.io_gpr & KVM_REG_MASK] = gpr;
vcpu->arch.qpr[vcpu->arch.io_gpr & KVM_REG_MASK] = gpr;
break;
#endif
default:
BUG();
}
}
int kvmppc_handle_load(struct kvm_run *run, struct kvm_vcpu *vcpu,
unsigned int rt, unsigned int bytes, int is_bigendian)
{
if (bytes > sizeof(run->mmio.data)) {
printk(KERN_ERR "%s: bad MMIO length: %d\n", __func__,
run->mmio.len);
}
run->mmio.phys_addr = vcpu->arch.paddr_accessed;
run->mmio.len = bytes;
run->mmio.is_write = 0;
vcpu->arch.io_gpr = rt;
vcpu->arch.mmio_is_bigendian = is_bigendian;
vcpu->mmio_needed = 1;
vcpu->mmio_is_write = 0;
vcpu->arch.mmio_sign_extend = 0;
return EMULATE_DO_MMIO;
}
/* Same as above, but sign extends */
int kvmppc_handle_loads(struct kvm_run *run, struct kvm_vcpu *vcpu,
unsigned int rt, unsigned int bytes, int is_bigendian)
{
int r;
r = kvmppc_handle_load(run, vcpu, rt, bytes, is_bigendian);
vcpu->arch.mmio_sign_extend = 1;
return r;
}
int kvmppc_handle_store(struct kvm_run *run, struct kvm_vcpu *vcpu,
u64 val, unsigned int bytes, int is_bigendian)
{
void *data = run->mmio.data;
if (bytes > sizeof(run->mmio.data)) {
printk(KERN_ERR "%s: bad MMIO length: %d\n", __func__,
run->mmio.len);
}
run->mmio.phys_addr = vcpu->arch.paddr_accessed;
run->mmio.len = bytes;
run->mmio.is_write = 1;
vcpu->mmio_needed = 1;
vcpu->mmio_is_write = 1;
/* Store the value at the lowest bytes in 'data'. */
if (is_bigendian) {
switch (bytes) {
case 8: *(u64 *)data = val; break;
case 4: *(u32 *)data = val; break;
case 2: *(u16 *)data = val; break;
case 1: *(u8 *)data = val; break;
}
} else {
/* Store LE value into 'data'. */
switch (bytes) {
case 4: st_le32(data, val); break;
case 2: st_le16(data, val); break;
case 1: *(u8 *)data = val; break;
}
}
return EMULATE_DO_MMIO;
}
int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
int r;
sigset_t sigsaved;
if (vcpu->sigset_active)
sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);
if (vcpu->mmio_needed) {
if (!vcpu->mmio_is_write)
kvmppc_complete_mmio_load(vcpu, run);
vcpu->mmio_needed = 0;
} else if (vcpu->arch.dcr_needed) {
if (!vcpu->arch.dcr_is_write)
kvmppc_complete_dcr_load(vcpu, run);
vcpu->arch.dcr_needed = 0;
} else if (vcpu->arch.osi_needed) {
u64 *gprs = run->osi.gprs;
int i;
for (i = 0; i < 32; i++)
kvmppc_set_gpr(vcpu, i, gprs[i]);
vcpu->arch.osi_needed = 0;
} else if (vcpu->arch.hcall_needed) {
int i;
kvmppc_set_gpr(vcpu, 3, run->papr_hcall.ret);
for (i = 0; i < 9; ++i)
kvmppc_set_gpr(vcpu, 4 + i, run->papr_hcall.args[i]);
vcpu->arch.hcall_needed = 0;
}
kvmppc_core_deliver_interrupts(vcpu);
r = kvmppc_vcpu_run(run, vcpu);
if (vcpu->sigset_active)
sigprocmask(SIG_SETMASK, &sigsaved, NULL);
return r;
}
int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu, struct kvm_interrupt *irq)
{
if (irq->irq == KVM_INTERRUPT_UNSET) {
kvmppc_core_dequeue_external(vcpu, irq);
return 0;
}
kvmppc_core_queue_external(vcpu, irq);
if (waitqueue_active(vcpu->arch.wqp)) {
wake_up_interruptible(vcpu->arch.wqp);
vcpu->stat.halt_wakeup++;
} else if (vcpu->cpu != -1) {
smp_send_reschedule(vcpu->cpu);
}
return 0;
}
static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
struct kvm_enable_cap *cap)
{
int r;
if (cap->flags)
return -EINVAL;
switch (cap->cap) {
case KVM_CAP_PPC_OSI:
r = 0;
vcpu->arch.osi_enabled = true;
break;
case KVM_CAP_PPC_PAPR:
r = 0;
vcpu->arch.papr_enabled = true;
break;
default:
r = -EINVAL;
break;
}
if (!r)
r = kvmppc_sanity_check(vcpu);
return r;
}
int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
struct kvm_mp_state *mp_state)
{
return -EINVAL;
}
int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
struct kvm_mp_state *mp_state)
{
return -EINVAL;
}
long kvm_arch_vcpu_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
struct kvm_vcpu *vcpu = filp->private_data;
void __user *argp = (void __user *)arg;
long r;
switch (ioctl) {
case KVM_INTERRUPT: {
struct kvm_interrupt irq;
r = -EFAULT;
if (copy_from_user(&irq, argp, sizeof(irq)))
goto out;
r = kvm_vcpu_ioctl_interrupt(vcpu, &irq);
goto out;
}
case KVM_ENABLE_CAP:
{
struct kvm_enable_cap cap;
r = -EFAULT;
if (copy_from_user(&cap, argp, sizeof(cap)))
goto out;
r = kvm_vcpu_ioctl_enable_cap(vcpu, &cap);
break;
}
default:
r = -EINVAL;
}
out:
return r;
}
static int kvm_vm_ioctl_get_pvinfo(struct kvm_ppc_pvinfo *pvinfo)
{
u32 inst_lis = 0x3c000000;
u32 inst_ori = 0x60000000;
u32 inst_nop = 0x60000000;
u32 inst_sc = 0x44000002;
u32 inst_imm_mask = 0xffff;
/*
* The hypercall to get into KVM from within guest context is as
* follows:
*
* lis r0, r0, KVM_SC_MAGIC_R0@h
* ori r0, KVM_SC_MAGIC_R0@l
* sc
* nop
*/
pvinfo->hcall[0] = inst_lis | ((KVM_SC_MAGIC_R0 >> 16) & inst_imm_mask);
pvinfo->hcall[1] = inst_ori | (KVM_SC_MAGIC_R0 & inst_imm_mask);
pvinfo->hcall[2] = inst_sc;
pvinfo->hcall[3] = inst_nop;
return 0;
}
long kvm_arch_vm_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
void __user *argp = (void __user *)arg;
long r;
switch (ioctl) {
case KVM_PPC_GET_PVINFO: {
struct kvm_ppc_pvinfo pvinfo;
memset(&pvinfo, 0, sizeof(pvinfo));
r = kvm_vm_ioctl_get_pvinfo(&pvinfo);
if (copy_to_user(argp, &pvinfo, sizeof(pvinfo))) {
r = -EFAULT;
goto out;
}
break;
}
#ifdef CONFIG_KVM_BOOK3S_64_HV
case KVM_CREATE_SPAPR_TCE: {
struct kvm_create_spapr_tce create_tce;
struct kvm *kvm = filp->private_data;
r = -EFAULT;
if (copy_from_user(&create_tce, argp, sizeof(create_tce)))
goto out;
r = kvm_vm_ioctl_create_spapr_tce(kvm, &create_tce);
goto out;
}
case KVM_ALLOCATE_RMA: {
struct kvm *kvm = filp->private_data;
struct kvm_allocate_rma rma;
r = kvm_vm_ioctl_allocate_rma(kvm, &rma);
if (r >= 0 && copy_to_user(argp, &rma, sizeof(rma)))
r = -EFAULT;
break;
}
#endif /* CONFIG_KVM_BOOK3S_64_HV */
default:
r = -ENOTTY;
}
out:
return r;
}
int kvm_arch_init(void *opaque)
{
return 0;
}
void kvm_arch_exit(void)
{
}