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Subject[PATCH 16/48] KVM: s390: streamline memslot handling
Date
From: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>

This patch relocates the variables kvm-s390 uses to track guest mem addr/size.
As discussed dropping the variables at struct kvm_arch level allows to use the
common vcpu->request based mechanism to reload guest memory if e.g. changes
via set_memory_region.

The kick mechanism introduced in this series is used to ensure running vcpus
leave guest state to catch the update.

Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/s390/include/asm/kvm_host.h | 4 +--
arch/s390/kvm/gaccess.h | 23 +++++++++--------
arch/s390/kvm/intercept.c | 6 ++--
arch/s390/kvm/kvm-s390.c | 50 ++++++++++++-------------------------
arch/s390/kvm/kvm-s390.h | 29 +++++++++++++++++++++-
arch/s390/kvm/sigp.c | 4 +-
6 files changed, 62 insertions(+), 54 deletions(-)
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 0a784f6..75535d4 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -1,7 +1,7 @@
/*
* asm-s390/kvm_host.h - definition for kernel virtual machines on s390
*
- * Copyright IBM Corp. 2008
+ * Copyright IBM Corp. 2008,2009
*
* 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)
@@ -228,8 +228,6 @@ struct kvm_vm_stat {
};

struct kvm_arch{
- unsigned long guest_origin;
- unsigned long guest_memsize;
struct sca_block *sca;
debug_info_t *dbf;
struct kvm_s390_float_interrupt float_int;
diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
index ed60f3a..03c716a 100644
--- a/arch/s390/kvm/gaccess.h
+++ b/arch/s390/kvm/gaccess.h
@@ -1,7 +1,7 @@
/*
* gaccess.h - access guest memory
*
- * Copyright IBM Corp. 2008
+ * Copyright IBM Corp. 2008,2009
*
* 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)
@@ -16,13 +16,14 @@
#include <linux/compiler.h>
#include <linux/kvm_host.h>
#include <asm/uaccess.h>
+#include "kvm-s390.h"

static inline void __user *__guestaddr_to_user(struct kvm_vcpu *vcpu,
unsigned long guestaddr)
{
unsigned long prefix = vcpu->arch.sie_block->prefix;
- unsigned long origin = vcpu->kvm->arch.guest_origin;
- unsigned long memsize = vcpu->kvm->arch.guest_memsize;
+ unsigned long origin = vcpu->arch.sie_block->gmsor;
+ unsigned long memsize = kvm_s390_vcpu_get_memsize(vcpu);

if (guestaddr < 2 * PAGE_SIZE)
guestaddr += prefix;
@@ -158,8 +159,8 @@ static inline int copy_to_guest(struct kvm_vcpu *vcpu, unsigned long guestdest,
const void *from, unsigned long n)
{
unsigned long prefix = vcpu->arch.sie_block->prefix;
- unsigned long origin = vcpu->kvm->arch.guest_origin;
- unsigned long memsize = vcpu->kvm->arch.guest_memsize;
+ unsigned long origin = vcpu->arch.sie_block->gmsor;
+ unsigned long memsize = kvm_s390_vcpu_get_memsize(vcpu);

if ((guestdest < 2 * PAGE_SIZE) && (guestdest + n > 2 * PAGE_SIZE))
goto slowpath;
@@ -209,8 +210,8 @@ static inline int copy_from_guest(struct kvm_vcpu *vcpu, void *to,
unsigned long guestsrc, unsigned long n)
{
unsigned long prefix = vcpu->arch.sie_block->prefix;
- unsigned long origin = vcpu->kvm->arch.guest_origin;
- unsigned long memsize = vcpu->kvm->arch.guest_memsize;
+ unsigned long origin = vcpu->arch.sie_block->gmsor;
+ unsigned long memsize = kvm_s390_vcpu_get_memsize(vcpu);

if ((guestsrc < 2 * PAGE_SIZE) && (guestsrc + n > 2 * PAGE_SIZE))
goto slowpath;
@@ -244,8 +245,8 @@ static inline int copy_to_guest_absolute(struct kvm_vcpu *vcpu,
unsigned long guestdest,
const void *from, unsigned long n)
{
- unsigned long origin = vcpu->kvm->arch.guest_origin;
- unsigned long memsize = vcpu->kvm->arch.guest_memsize;
+ unsigned long origin = vcpu->arch.sie_block->gmsor;
+ unsigned long memsize = kvm_s390_vcpu_get_memsize(vcpu);

if (guestdest + n > memsize)
return -EFAULT;
@@ -262,8 +263,8 @@ static inline int copy_from_guest_absolute(struct kvm_vcpu *vcpu, void *to,
unsigned long guestsrc,
unsigned long n)
{
- unsigned long origin = vcpu->kvm->arch.guest_origin;
- unsigned long memsize = vcpu->kvm->arch.guest_memsize;
+ unsigned long origin = vcpu->arch.sie_block->gmsor;
+ unsigned long memsize = kvm_s390_vcpu_get_memsize(vcpu);

if (guestsrc + n > memsize)
return -EFAULT;
diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 0732ab4..ba9d8a7 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -1,7 +1,7 @@
/*
* intercept.c - in-kernel handling for sie intercepts
*
- * Copyright IBM Corp. 2008
+ * Copyright IBM Corp. 2008,2009
*
* 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)
@@ -164,9 +164,9 @@ static int handle_validity(struct kvm_vcpu *vcpu)

vcpu->stat.exit_validity++;
if ((viwhy == 0x37) && (vcpu->arch.sie_block->prefix
- <= vcpu->kvm->arch.guest_memsize - 2*PAGE_SIZE)){
+ <= kvm_s390_vcpu_get_memsize(vcpu) - 2*PAGE_SIZE)) {
rc = fault_in_pages_writeable((char __user *)
- vcpu->kvm->arch.guest_origin +
+ vcpu->arch.sie_block->gmsor +
vcpu->arch.sie_block->prefix,
2*PAGE_SIZE);
if (rc)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 5c1c302..098bfa6 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1,7 +1,7 @@
/*
* s390host.c -- hosting zSeries kernel virtual machines
*
- * Copyright IBM Corp. 2008
+ * Copyright IBM Corp. 2008,2009
*
* 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)
@@ -10,6 +10,7 @@
* Author(s): Carsten Otte <cotte@de.ibm.com>
* Christian Borntraeger <borntraeger@de.ibm.com>
* Heiko Carstens <heiko.carstens@de.ibm.com>
+ * Christian Ehrhardt <ehrhardt@de.ibm.com>
*/

#include <linux/compiler.h>
@@ -278,16 +279,10 @@ static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu)
vcpu->arch.sie_block->gbea = 1;
}

-/* The current code can have up to 256 pages for virtio */
-#define VIRTIODESCSPACE (256ul * 4096ul)
-
int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
{
atomic_set(&vcpu->arch.sie_block->cpuflags, CPUSTAT_ZARCH);
- vcpu->arch.sie_block->gmslm = vcpu->kvm->arch.guest_memsize +
- vcpu->kvm->arch.guest_origin +
- VIRTIODESCSPACE - 1ul;
- vcpu->arch.sie_block->gmsor = vcpu->kvm->arch.guest_origin;
+ set_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests);
vcpu->arch.sie_block->ecb = 2;
vcpu->arch.sie_block->eca = 0xC1002001U;
vcpu->arch.sie_block->fac = (int) (long) facilities;
@@ -491,9 +486,14 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
vcpu_load(vcpu);

rerun_vcpu:
+ if (vcpu->requests)
+ if (test_and_clear_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests))
+ kvm_s390_vcpu_set_mem(vcpu);
+
/* verify, that memory has been registered */
- if (!vcpu->kvm->arch.guest_memsize) {
+ if (!vcpu->arch.sie_block->gmslm) {
vcpu_put(vcpu);
+ VCPU_EVENT(vcpu, 3, "%s", "no memory registered to run vcpu");
return -EINVAL;
}

@@ -691,7 +691,7 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
vmas. It is okay to mmap() and munmap() stuff in this slot after
doing this call at any time */

- if (mem->slot || kvm->arch.guest_memsize)
+ if (mem->slot)
return -EINVAL;

if (mem->guest_phys_addr)
@@ -706,36 +706,18 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
if (!user_alloc)
return -EINVAL;

- /* lock all vcpus */
- for (i = 0; i < KVM_MAX_VCPUS; ++i) {
- if (!kvm->vcpus[i])
- continue;
- if (!mutex_trylock(&kvm->vcpus[i]->mutex))
- goto fail_out;
- }
-
- kvm->arch.guest_origin = mem->userspace_addr;
- kvm->arch.guest_memsize = mem->memory_size;
-
- /* update sie control blocks, and unlock all vcpus */
+ /* request update of sie control block for all available vcpus */
for (i = 0; i < KVM_MAX_VCPUS; ++i) {
if (kvm->vcpus[i]) {
- kvm->vcpus[i]->arch.sie_block->gmsor =
- kvm->arch.guest_origin;
- kvm->vcpus[i]->arch.sie_block->gmslm =
- kvm->arch.guest_memsize +
- kvm->arch.guest_origin +
- VIRTIODESCSPACE - 1ul;
- mutex_unlock(&kvm->vcpus[i]->mutex);
+ if (test_and_set_bit(KVM_REQ_MMU_RELOAD,
+ &kvm->vcpus[i]->requests))
+ continue;
+ kvm_s390_inject_sigp_stop(kvm->vcpus[i],
+ ACTION_RELOADVCPU_ON_STOP);
}
}

return 0;
-
-fail_out:
- for (; i >= 0; i--)
- mutex_unlock(&kvm->vcpus[i]->mutex);
- return -EINVAL;
}

void kvm_arch_flush_shadow(struct kvm *kvm)
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 2072cd4..ec5eee7 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -1,7 +1,7 @@
/*
* kvm_s390.h - definition for kvm on s390
*
- * Copyright IBM Corp. 2008
+ * Copyright IBM Corp. 2008,2009
*
* 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)
@@ -9,6 +9,7 @@
*
* Author(s): Carsten Otte <cotte@de.ibm.com>
* Christian Borntraeger <borntraeger@de.ibm.com>
+ * Christian Ehrhardt <ehrhardt@de.ibm.com>
*/

#ifndef ARCH_S390_KVM_S390_H
@@ -18,6 +19,9 @@
#include <linux/kvm.h>
#include <linux/kvm_host.h>

+/* The current code can have up to 256 pages for virtio */
+#define VIRTIODESCSPACE (256ul * 4096ul)
+
typedef int (*intercept_handler_t)(struct kvm_vcpu *vcpu);

/* negativ values are error codes, positive values for internal conditions */
@@ -54,6 +58,29 @@ int kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu,
int kvm_s390_inject_program_int(struct kvm_vcpu *vcpu, u16 code);
int kvm_s390_inject_sigp_stop(struct kvm_vcpu *vcpu, int action);

+static inline int kvm_s390_vcpu_get_memsize(struct kvm_vcpu *vcpu)
+{
+ return vcpu->arch.sie_block->gmslm
+ - vcpu->arch.sie_block->gmsor
+ - VIRTIODESCSPACE + 1ul;
+}
+
+static inline void kvm_s390_vcpu_set_mem(struct kvm_vcpu *vcpu)
+{
+ struct kvm_memory_slot *mem;
+
+ down_read(&vcpu->kvm->slots_lock);
+ mem = &vcpu->kvm->memslots[0];
+
+ vcpu->arch.sie_block->gmsor = mem->userspace_addr;
+ vcpu->arch.sie_block->gmslm =
+ mem->userspace_addr +
+ (mem->npages << PAGE_SHIFT) +
+ VIRTIODESCSPACE - 1ul;
+
+ up_read(&vcpu->kvm->slots_lock);
+}
+
/* implemented in priv.c */
int kvm_s390_handle_b2(struct kvm_vcpu *vcpu);

diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c
index 21897b0..40c8c67 100644
--- a/arch/s390/kvm/sigp.c
+++ b/arch/s390/kvm/sigp.c
@@ -189,9 +189,9 @@ static int __sigp_set_prefix(struct kvm_vcpu *vcpu, u16 cpu_addr, u32 address,
/* make sure that the new value is valid memory */
address = address & 0x7fffe000u;
if ((copy_from_guest(vcpu, &tmp,
- (u64) (address + vcpu->kvm->arch.guest_origin) , 1)) ||
+ (u64) (address + vcpu->arch.sie_block->gmsor) , 1)) ||
(copy_from_guest(vcpu, &tmp, (u64) (address +
- vcpu->kvm->arch.guest_origin + PAGE_SIZE), 1))) {
+ vcpu->arch.sie_block->gmsor + PAGE_SIZE), 1))) {
*reg |= SIGP_STAT_INVALID_PARAMETER;
return 1; /* invalid parameter */
}
--
1.6.3.3


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