[PATCH v1 RFC 3/6] KVM: s390: use facilities and cpu_id per KVM

From: Michael Mueller
Date: Tue May 13 2014 - 11:00:29 EST

The patch introduces facilities and cpu_ids per virtual machine.
Different virtual machines may want to expose different facilities and
cpu ids to the guest, so let's make them per-vm instead of global.

In addition this patch renames all ocurrences of *facilities to *fac_list
smilar to the already exiting symbol stfl_fac_list in lowcore.

Signed-off-by: Michael Mueller <mimu@xxxxxxxxxxxxxxxxxx>
Acked-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
arch/s390/include/asm/kvm_host.h | 7 +++
arch/s390/kvm/gaccess.c | 4 +-
arch/s390/kvm/kvm-s390.c | 107 +++++++++++++++++++++++++++------------
arch/s390/kvm/kvm-s390.h | 23 +++++++--
arch/s390/kvm/priv.c | 13 +++--
5 files changed, 113 insertions(+), 41 deletions(-)

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 38d487a..b4751ba 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -414,6 +414,12 @@ struct kvm_s390_config {
struct kvm_s390_attr_name name;
};

+struct kvm_s390_cpu_model {
+ unsigned long *sie_fac;
+ struct cpuid cpu_id;
+ unsigned long *fac_list;
+};
+
struct kvm_arch{
struct sca_block *sca;
debug_info_t *dbf;
@@ -427,6 +433,7 @@ struct kvm_arch{
wait_queue_head_t ipte_wq;
struct kvm_s390_config *cfg;
spinlock_t start_stop_lock;
+ struct kvm_s390_cpu_model model;
};

#define KVM_HVA_ERR_BAD (-1UL)
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index db608c3..4c7ca40 100644
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -358,8 +358,8 @@ static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
union asce asce;

ctlreg0.val = vcpu->arch.sie_block->gcr[0];
- edat1 = ctlreg0.edat && test_vfacility(8);
- edat2 = edat1 && test_vfacility(78);
+ edat1 = ctlreg0.edat && test_kvm_facility(vcpu->kvm, 8);
+ edat2 = edat1 && test_kvm_facility(vcpu->kvm, 78);
asce.val = get_vcpu_asce(vcpu);
if (asce.r)
goto real_address;
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 01a5212..a53652f 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1,5 +1,5 @@
/*
- * hosting zSeries kernel virtual machines
+ * Hosting zSeries kernel virtual machines
*
* Copyright IBM Corp. 2008, 2009
*
@@ -30,7 +30,6 @@
#include <asm/pgtable.h>
#include <asm/nmi.h>
#include <asm/switch_to.h>
-#include <asm/facility.h>
#include <asm/sclp.h>
#include<asm/timex.h>
#include "kvm-s390.h"
@@ -92,15 +91,33 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
{ NULL }
};

-unsigned long *vfacilities;
-static struct gmap_notifier gmap_notifier;
+/* upper facilities limit for kvm */
+unsigned long kvm_s390_fac_list_mask[] = {
+ 0xff82fff3f47c2000UL,
+ 0x005c000000000000UL,
+};
+
+unsigned long kvm_s390_fac_list_mask_size(void)
+{
+ BUILD_BUG_ON(ARRAY_SIZE(kvm_s390_fac_list_mask) >
+ S390_ARCH_FAC_MASK_SIZE_U64);
+ return ARRAY_SIZE(kvm_s390_fac_list_mask);
+}

-/* test availability of vfacility */
-int test_vfacility(unsigned long nr)
+void kvm_s390_apply_fac_list_mask(unsigned long fac_list[])
{
- return __test_facility(nr, (void *) vfacilities);
+ unsigned int i;
+
+ for (i = 0; i < S390_ARCH_FAC_LIST_SIZE_U64; i++) {
+ if (i < kvm_s390_fac_list_mask_size())
+ fac_list[i] &= kvm_s390_fac_list_mask[i];
+ else
+ fac_list[i] &= 0UL;
+ }
}

+static struct gmap_notifier gmap_notifier;
+
/* Section: not file related */
int kvm_arch_hardware_enable(void *garbage)
{
@@ -485,6 +502,30 @@ long kvm_arch_vm_ioctl(struct file *filp,
return r;
}

+/* make sure the memory used for fac_list is zeroed */
+void kvm_s390_get_hard_fac_list(unsigned long *fac_list, int size)
+{
+ int i;
+
+ if (!test_facility(7))
+ memcpy(fac_list, &S390_lowcore.stfl_fac_list, 4);
+ else {
+ register unsigned long reg0 asm("0") = size - 1;
+ asm volatile(".insn s,0xb2b00000,0(%1)" /* stfle */
+ : "+d" (reg0)
+ : "a" (fac_list)
+ : "memory", "cc");
+ }
+ for (i = 0; i < size && i < kvm_s390_fac_list_mask_size(); i++)
+ fac_list[i] &= kvm_s390_fac_list_mask[i];
+}
+
+static void kvm_s390_get_cpu_id(struct cpuid *cpu_id)
+{
+ get_cpu_id(cpu_id);
+ cpu_id->version = 0xff;
+}
+
int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
{
int rc;
@@ -522,6 +563,23 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
if (!kvm->arch.dbf)
goto out_nodbf;

+ /*
+ * The architected maximum amount of facilities is 16 kbit. To store
+ * this amount, 2 kbyte of memory is required. Thus we need a full
+ * page to hold the active copy (arch.model.sie_fac) and the current
+ * facilities set (arch.model.facilities).
+ */
+ kvm->arch.model.sie_fac = (unsigned long *)
+ get_zeroed_page(GFP_KERNEL|GFP_DMA);
+ if (!kvm->arch.model.sie_fac)
+ goto out_nofac;
+
+ kvm->arch.model.fac_list = kvm->arch.model.sie_fac;
+ kvm->arch.model.fac_list += S390_ARCH_FAC_LIST_SIZE_U64;
+ kvm_s390_get_hard_fac_list(kvm->arch.model.fac_list,
+ kvm_s390_fac_list_mask_size());
+ kvm_s390_get_cpu_id(&kvm->arch.model.cpu_id);
+
spin_lock_init(&kvm->arch.float_int.lock);
INIT_LIST_HEAD(&kvm->arch.float_int.list);
init_waitqueue_head(&kvm->arch.ipte_wq);
@@ -554,6 +612,8 @@ out_gmap:
out_nogmap:
debug_unregister(kvm->arch.dbf);
out_nodbf:
+ free_page((unsigned long)kvm->arch.model.sie_fac);
+out_nofac:
free_page((unsigned long)(kvm->arch.sca));
out_err:
return rc;
@@ -608,6 +668,7 @@ void kvm_arch_sync_events(struct kvm *kvm)
void kvm_arch_destroy_vm(struct kvm *kvm)
{
kvm_free_vcpus(kvm);
+ free_page((unsigned long)kvm->arch.model.sie_fac);
free_page((unsigned long)(kvm->arch.sca));
debug_unregister(kvm->arch.dbf);
if (!kvm_is_ucontrol(kvm))
@@ -720,14 +781,14 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
CPUSTAT_STOPPED |
CPUSTAT_GED);
vcpu->arch.sie_block->ecb = 6;
- if (test_vfacility(50) && test_vfacility(73))
+ if (test_kvm_facility(vcpu->kvm, 50) &&
+ test_kvm_facility(vcpu->kvm, 73))
vcpu->arch.sie_block->ecb |= 0x10;

vcpu->arch.sie_block->ecb2 = 8;
vcpu->arch.sie_block->eca = 0xD1002000U;
if (sclp_has_siif())
vcpu->arch.sie_block->eca |= 1;
- vcpu->arch.sie_block->fac = (int) (long) vfacilities;
vcpu->arch.sie_block->ictl |= ICTL_ISKE | ICTL_SSKE | ICTL_RRBE |
ICTL_TPROT;

@@ -740,8 +801,10 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
tasklet_init(&vcpu->arch.tasklet, kvm_s390_tasklet,
(unsigned long) vcpu);
vcpu->arch.ckc_timer.function = kvm_s390_idle_wakeup;
- get_cpu_id(&vcpu->arch.cpu_id);
- vcpu->arch.cpu_id.version = 0xff;
+ vcpu->arch.cpu_id = vcpu->kvm->arch.model.cpu_id;
+ memcpy(vcpu->kvm->arch.model.sie_fac, vcpu->kvm->arch.model.fac_list,
+ S390_ARCH_FAC_LIST_SIZE_BYTE);
+
return rc;
}

@@ -782,6 +845,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
vcpu->arch.sie_block->scaol = (__u32)(__u64)kvm->arch.sca;
set_bit(63 - id, (unsigned long *) &kvm->arch.sca->mcn);
}
+ vcpu->arch.sie_block->fac = (int) (long) kvm->arch.model.sie_fac;

spin_lock_init(&vcpu->arch.local_int.lock);
INIT_LIST_HEAD(&vcpu->arch.local_int.list);
@@ -1841,30 +1905,11 @@ void kvm_arch_flush_shadow_memslot(struct kvm *kvm,

static int __init kvm_s390_init(void)
{
- int ret;
- ret = kvm_init(NULL, sizeof(struct kvm_vcpu), 0, THIS_MODULE);
- if (ret)
- return ret;
-
- /*
- * guests can ask for up to 255+1 double words, we need a full page
- * to hold the maximum amount of facilities. On the other hand, we
- * only set facilities that are known to work in KVM.
- */
- vfacilities = (unsigned long *) get_zeroed_page(GFP_KERNEL|GFP_DMA);
- if (!vfacilities) {
- kvm_exit();
- return -ENOMEM;
- }
- memcpy(vfacilities, S390_lowcore.stfle_fac_list, 16);
- vfacilities[0] &= 0xff82fff3f4fc2000UL;
- vfacilities[1] &= 0x005c000000000000UL;
- return 0;
+ return kvm_init(NULL, sizeof(struct kvm_vcpu), 0, THIS_MODULE);
}

static void __exit kvm_s390_exit(void)
{
- free_page((unsigned long) vfacilities);
kvm_exit();
}

diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 066fdbc..ecadc8a 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -18,14 +18,20 @@
#include <linux/hrtimer.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
+#include <asm/facility.h>

typedef int (*intercept_handler_t)(struct kvm_vcpu *vcpu);

-/* declare vfacilities extern */
-extern unsigned long *vfacilities;
-
int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu);

+/* maximum size of facilities and facility mask is 2k bytes */
+#define S390_ARCH_FAC_LIST_SIZE_BYTE (1<<11)
+#define S390_ARCH_FAC_LIST_SIZE_U64 \
+ (S390_ARCH_FAC_LIST_SIZE_BYTE / sizeof(u64))
+#define S390_ARCH_FAC_MASK_SIZE_BYTE S390_ARCH_FAC_LIST_SIZE_BYTE
+#define S390_ARCH_FAC_MASK_SIZE_U64 \
+ (S390_ARCH_FAC_MASK_SIZE_BYTE / sizeof(u64))
+
/* Transactional Memory Execution related macros */
#define IS_TE_ENABLED(vcpu) ((vcpu->arch.sie_block->ecb & 0x10))
#define TDB_FORMAT1 1
@@ -129,6 +135,12 @@ static inline void kvm_s390_set_psw_cc(struct kvm_vcpu *vcpu, unsigned long cc)
vcpu->arch.sie_block->gpsw.mask |= cc << 44;
}

+/* test availability of kvm facility */
+static inline int test_kvm_facility(struct kvm *kvm, unsigned long nr)
+{
+ return __test_facility(nr, kvm->arch.model.fac_list);
+}
+
int kvm_s390_handle_wait(struct kvm_vcpu *vcpu);
enum hrtimer_restart kvm_s390_idle_wakeup(struct hrtimer *timer);
void kvm_s390_tasklet(unsigned long parm);
@@ -177,7 +189,10 @@ int kvm_s390_vcpu_setup_cmma(struct kvm_vcpu *vcpu);
void kvm_s390_vcpu_unsetup_cmma(struct kvm_vcpu *vcpu);
/* is cmma enabled */
bool kvm_s390_cmma_enabled(struct kvm *kvm);
-int test_vfacility(unsigned long nr);
+unsigned long kvm_s390_fac_list__mask_size(void);
+void kvm_s390_apply_fac_list_mask(unsigned long fac_list[]);
+extern unsigned long kvm_s390_fac_list_mask[];
+void kvm_s390_get_hard_fac_list(unsigned long *fac_list, int size);

/* implemented in diag.c */
int kvm_s390_handle_diag(struct kvm_vcpu *vcpu);
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 19f3475..2de5baf 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -337,19 +337,24 @@ static int handle_io_inst(struct kvm_vcpu *vcpu)
static int handle_stfl(struct kvm_vcpu *vcpu)
{
int rc;
+ unsigned int fac;

vcpu->stat.instruction_stfl++;

if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);

+ /*
+ * We need to shift the lower 32 facility bits (bit 0-31) from a u64
+ * into a u32 memory representation. They will remain bits 0-31.
+ */
+ fac = *vcpu->kvm->arch.model.sie_fac >> 32;
rc = write_guest_lc(vcpu, offsetof(struct _lowcore, stfl_fac_list),
- vfacilities, 4);
+ &fac, sizeof(fac));
if (rc)
return rc;
- VCPU_EVENT(vcpu, 5, "store facility list value %x",
- *(unsigned int *) vfacilities);
- trace_kvm_s390_handle_stfl(vcpu, *(unsigned int *) vfacilities);
+ VCPU_EVENT(vcpu, 5, "store facility list value %x", fac);
+ trace_kvm_s390_handle_stfl(vcpu, fac);
return 0;
}

--
1.8.3.1

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