aboutsummaryrefslogtreecommitdiffstats
path: root/arch/s390/kvm
diff options
context:
space:
mode:
Diffstat (limited to 'arch/s390/kvm')
-rw-r--r--arch/s390/kvm/Makefile2
-rw-r--r--arch/s390/kvm/kvm-s390.c15
-rw-r--r--arch/s390/kvm/kvm-s390.h7
-rw-r--r--arch/s390/kvm/priv.c1
-rw-r--r--arch/s390/kvm/vsie.c755
5 files changed, 779 insertions, 1 deletions
diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile
index 82e73e2b953d..09a9e6dfc09f 100644
--- a/arch/s390/kvm/Makefile
+++ b/arch/s390/kvm/Makefile
@@ -12,6 +12,6 @@ common-objs = $(KVM)/kvm_main.o $(KVM)/eventfd.o $(KVM)/async_pf.o $(KVM)/irqch
ccflags-y := -Ivirt/kvm -Iarch/s390/kvm
kvm-objs := $(common-objs) kvm-s390.o intercept.o interrupt.o priv.o sigp.o
-kvm-objs += diag.o gaccess.o guestdbg.o sthyi.o
+kvm-objs += diag.o gaccess.o guestdbg.o sthyi.o vsie.o
obj-$(CONFIG_KVM) += kvm.o
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index a890f7d20711..3fb124226e97 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -99,6 +99,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
{ "instruction_stfl", VCPU_STAT(instruction_stfl) },
{ "instruction_tprot", VCPU_STAT(instruction_tprot) },
{ "instruction_sthyi", VCPU_STAT(instruction_sthyi) },
+ { "instruction_sie", VCPU_STAT(instruction_sie) },
{ "instruction_sigp_sense", VCPU_STAT(instruction_sigp_sense) },
{ "instruction_sigp_sense_running", VCPU_STAT(instruction_sigp_sense_running) },
{ "instruction_sigp_external_call", VCPU_STAT(instruction_sigp_external_call) },
@@ -142,6 +143,7 @@ static DECLARE_BITMAP(kvm_s390_available_cpu_feat, KVM_S390_VM_CPU_FEAT_NR_BITS)
static struct kvm_s390_vm_cpu_subfunc kvm_s390_available_subfunc;
static struct gmap_notifier gmap_notifier;
+static struct gmap_notifier vsie_gmap_notifier;
debug_info_t *kvm_s390_dbf;
/* Section: not file related */
@@ -187,6 +189,8 @@ int kvm_arch_hardware_setup(void)
{
gmap_notifier.notifier_call = kvm_gmap_notifier;
gmap_register_pte_notifier(&gmap_notifier);
+ vsie_gmap_notifier.notifier_call = kvm_s390_vsie_gmap_notifier;
+ gmap_register_pte_notifier(&vsie_gmap_notifier);
atomic_notifier_chain_register(&s390_epoch_delta_notifier,
&kvm_clock_notifier);
return 0;
@@ -195,6 +199,7 @@ int kvm_arch_hardware_setup(void)
void kvm_arch_hardware_unsetup(void)
{
gmap_unregister_pte_notifier(&gmap_notifier);
+ gmap_unregister_pte_notifier(&vsie_gmap_notifier);
atomic_notifier_chain_unregister(&s390_epoch_delta_notifier,
&kvm_clock_notifier);
}
@@ -252,6 +257,14 @@ static void kvm_s390_cpu_feat_init(void)
if (MACHINE_HAS_ESOP)
allow_cpu_feat(KVM_S390_VM_CPU_FEAT_ESOP);
+ /*
+ * We need SIE support, ESOP (PROT_READ protection for gmap_shadow),
+ * 64bit SCAO (SCA passthrough) and IDTE (for gmap_shadow unshadowing).
+ */
+ if (!sclp.has_sief2 || !MACHINE_HAS_ESOP || !sclp.has_64bscao ||
+ !test_facility(3))
+ return;
+ allow_cpu_feat(KVM_S390_VM_CPU_FEAT_SIEF2);
}
int kvm_arch_init(void *opaque)
@@ -1406,6 +1419,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
kvm->arch.epoch = 0;
spin_lock_init(&kvm->arch.start_stop_lock);
+ kvm_s390_vsie_init(kvm);
KVM_EVENT(3, "vm 0x%pK created by pid %u", kvm, current->pid);
return 0;
@@ -1463,6 +1477,7 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
gmap_remove(kvm->arch.gmap);
kvm_s390_destroy_adapters(kvm);
kvm_s390_clear_float_irqs(kvm);
+ kvm_s390_vsie_destroy(kvm);
KVM_EVENT(3, "vm 0x%pK destroyed", kvm);
}
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 52aa47e112d8..b137fbaac91c 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -252,6 +252,13 @@ int kvm_s390_handle_stctl(struct kvm_vcpu *vcpu);
int kvm_s390_handle_lctl(struct kvm_vcpu *vcpu);
int kvm_s390_handle_eb(struct kvm_vcpu *vcpu);
+/* implemented in vsie.c */
+int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu);
+void kvm_s390_vsie_gmap_notifier(struct gmap *gmap, unsigned long start,
+ unsigned long end);
+void kvm_s390_vsie_init(struct kvm *kvm);
+void kvm_s390_vsie_destroy(struct kvm *kvm);
+
/* implemented in sigp.c */
int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu);
int kvm_s390_handle_sigp_pei(struct kvm_vcpu *vcpu);
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 3db3be139992..c77ad2dc334f 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -719,6 +719,7 @@ static const intercept_handler_t b2_handlers[256] = {
[0x10] = handle_set_prefix,
[0x11] = handle_store_prefix,
[0x12] = handle_store_cpu_address,
+ [0x14] = kvm_s390_handle_vsie,
[0x21] = handle_ipte_interlock,
[0x29] = handle_iske,
[0x2a] = handle_rrbe,
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
new file mode 100644
index 000000000000..747d4f900155
--- /dev/null
+++ b/arch/s390/kvm/vsie.c
@@ -0,0 +1,755 @@
+/*
+ * kvm nested virtualization support for s390x
+ *
+ * Copyright IBM Corp. 2016
+ *
+ * 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): David Hildenbrand <dahi@linux.vnet.ibm.com>
+ */
+#include <linux/vmalloc.h>
+#include <linux/kvm_host.h>
+#include <linux/bug.h>
+#include <linux/list.h>
+#include <linux/bitmap.h>
+#include <asm/gmap.h>
+#include <asm/mmu_context.h>
+#include <asm/sclp.h>
+#include <asm/nmi.h>
+#include "kvm-s390.h"
+#include "gaccess.h"
+
+struct vsie_page {
+ struct kvm_s390_sie_block scb_s; /* 0x0000 */
+ /* the pinned originial scb */
+ struct kvm_s390_sie_block *scb_o; /* 0x0200 */
+ /* the shadow gmap in use by the vsie_page */
+ struct gmap *gmap; /* 0x0208 */
+ __u8 reserved[0x1000 - 0x0210]; /* 0x0210 */
+} __packed;
+
+/* trigger a validity icpt for the given scb */
+static int set_validity_icpt(struct kvm_s390_sie_block *scb,
+ __u16 reason_code)
+{
+ scb->ipa = 0x1000;
+ scb->ipb = ((__u32) reason_code) << 16;
+ scb->icptcode = ICPT_VALIDITY;
+ return 1;
+}
+
+/* mark the prefix as unmapped, this will block the VSIE */
+static void prefix_unmapped(struct vsie_page *vsie_page)
+{
+ atomic_or(PROG_REQUEST, &vsie_page->scb_s.prog20);
+}
+
+/* mark the prefix as unmapped and wait until the VSIE has been left */
+static void prefix_unmapped_sync(struct vsie_page *vsie_page)
+{
+ prefix_unmapped(vsie_page);
+ if (vsie_page->scb_s.prog0c & PROG_IN_SIE)
+ atomic_or(CPUSTAT_STOP_INT, &vsie_page->scb_s.cpuflags);
+ while (vsie_page->scb_s.prog0c & PROG_IN_SIE)
+ cpu_relax();
+}
+
+/* mark the prefix as mapped, this will allow the VSIE to run */
+static void prefix_mapped(struct vsie_page *vsie_page)
+{
+ atomic_andnot(PROG_REQUEST, &vsie_page->scb_s.prog20);
+}
+
+
+/* copy the updated intervention request bits into the shadow scb */
+static void update_intervention_requests(struct vsie_page *vsie_page)
+{
+ const int bits = CPUSTAT_STOP_INT | CPUSTAT_IO_INT | CPUSTAT_EXT_INT;
+ int cpuflags;
+
+ cpuflags = atomic_read(&vsie_page->scb_o->cpuflags);
+ atomic_andnot(bits, &vsie_page->scb_s.cpuflags);
+ atomic_or(cpuflags & bits, &vsie_page->scb_s.cpuflags);
+}
+
+/* shadow (filter and validate) the cpuflags */
+static int prepare_cpuflags(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+ struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+ struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+ int newflags, cpuflags = atomic_read(&scb_o->cpuflags);
+
+ /* we don't allow ESA/390 guests */
+ if (!(cpuflags & CPUSTAT_ZARCH))
+ return set_validity_icpt(scb_s, 0x0001U);
+
+ if (cpuflags & (CPUSTAT_RRF | CPUSTAT_MCDS))
+ return set_validity_icpt(scb_s, 0x0001U);
+ else if (cpuflags & (CPUSTAT_SLSV | CPUSTAT_SLSR))
+ return set_validity_icpt(scb_s, 0x0007U);
+
+ /* intervention requests will be set later */
+ newflags = CPUSTAT_ZARCH;
+
+ atomic_set(&scb_s->cpuflags, newflags);
+ return 0;
+}
+
+/* unshadow the scb, copying parameters back to the real scb */
+static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+ struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+ struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+
+ /* interception */
+ scb_o->icptcode = scb_s->icptcode;
+ scb_o->icptstatus = scb_s->icptstatus;
+ scb_o->ipa = scb_s->ipa;
+ scb_o->ipb = scb_s->ipb;
+ scb_o->gbea = scb_s->gbea;
+
+ /* timer */
+ scb_o->cputm = scb_s->cputm;
+ scb_o->ckc = scb_s->ckc;
+ scb_o->todpr = scb_s->todpr;
+
+ /* guest state */
+ scb_o->gpsw = scb_s->gpsw;
+ scb_o->gg14 = scb_s->gg14;
+ scb_o->gg15 = scb_s->gg15;
+ memcpy(scb_o->gcr, scb_s->gcr, 128);
+ scb_o->pp = scb_s->pp;
+
+ /* interrupt intercept */
+ switch (scb_s->icptcode) {
+ case ICPT_PROGI:
+ case ICPT_INSTPROGI:
+ case ICPT_EXTINT:
+ memcpy((void *)((u64)scb_o + 0xc0),
+ (void *)((u64)scb_s + 0xc0), 0xf0 - 0xc0);
+ break;
+ case ICPT_PARTEXEC:
+ /* MVPG only */
+ memcpy((void *)((u64)scb_o + 0xc0),
+ (void *)((u64)scb_s + 0xc0), 0xd0 - 0xc0);
+ break;
+ }
+
+ if (scb_s->ihcpu != 0xffffU)
+ scb_o->ihcpu = scb_s->ihcpu;
+}
+
+/*
+ * Setup the shadow scb by copying and checking the relevant parts of the g2
+ * provided scb.
+ *
+ * Returns: - 0 if the scb has been shadowed
+ * - > 0 if control has to be given to guest 2
+ */
+static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+ struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+ struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+ int rc;
+
+ /* make sure we don't have any leftovers when reusing the scb */
+ scb_s->icptcode = 0;
+ scb_s->eca = 0;
+ scb_s->ecb = 0;
+ scb_s->ecb2 = 0;
+ scb_s->ecb3 = 0;
+ scb_s->ecd = 0;
+
+ rc = prepare_cpuflags(vcpu, vsie_page);
+ if (rc)
+ goto out;
+
+ /* timer */
+ scb_s->cputm = scb_o->cputm;
+ scb_s->ckc = scb_o->ckc;
+ scb_s->todpr = scb_o->todpr;
+ scb_s->epoch = scb_o->epoch;
+
+ /* guest state */
+ scb_s->gpsw = scb_o->gpsw;
+ scb_s->gg14 = scb_o->gg14;
+ scb_s->gg15 = scb_o->gg15;
+ memcpy(scb_s->gcr, scb_o->gcr, 128);
+ scb_s->pp = scb_o->pp;
+
+ /* interception / execution handling */
+ scb_s->gbea = scb_o->gbea;
+ scb_s->lctl = scb_o->lctl;
+ scb_s->svcc = scb_o->svcc;
+ scb_s->ictl = scb_o->ictl;
+ /*
+ * SKEY handling functions can't deal with false setting of PTE invalid
+ * bits. Therefore we cannot provide interpretation and would later
+ * have to provide own emulation handlers.
+ */
+ scb_s->ictl |= ICTL_ISKE | ICTL_SSKE | ICTL_RRBE;
+ scb_s->icpua = scb_o->icpua;
+
+ /* SIE will do mso/msl validity and exception checks for us */
+ scb_s->msl = scb_o->msl & 0xfffffffffff00000UL;
+ scb_s->mso = scb_o->mso & 0xfffffffffff00000UL;
+ scb_s->prefix = scb_o->prefix;
+
+ /* We have to definetly flush the tlb if this scb never ran */
+ if (scb_s->ihcpu != 0xffffU)
+ scb_s->ihcpu = scb_o->ihcpu;
+
+ /* MVPG and Protection Exception Interpretation are always available */
+ scb_s->eca |= scb_o->eca & 0x01002000U;
+
+out:
+ if (rc)
+ unshadow_scb(vcpu, vsie_page);
+ return rc;
+}
+
+void kvm_s390_vsie_gmap_notifier(struct gmap *gmap, unsigned long start,
+ unsigned long end)
+{
+ struct kvm *kvm = gmap->private;
+ struct vsie_page *cur;
+ unsigned long prefix;
+ struct page *page;
+ int i;
+
+ if (!gmap_is_shadow(gmap))
+ return;
+ if (start >= 1UL << 31)
+ /* We are only interested in prefix pages */
+ return;
+
+ /*
+ * Only new shadow blocks are added to the list during runtime,
+ * therefore we can safely reference them all the time.
+ */
+ for (i = 0; i < kvm->arch.vsie.page_count; i++) {
+ page = READ_ONCE(kvm->arch.vsie.pages[i]);
+ if (!page)
+ continue;
+ cur = page_to_virt(page);
+ if (READ_ONCE(cur->gmap) != gmap)
+ continue;
+ prefix = cur->scb_s.prefix << GUEST_PREFIX_SHIFT;
+ /* with mso/msl, the prefix lies at an offset */
+ prefix += cur->scb_s.mso;
+ if (prefix <= end && start <= prefix + PAGE_SIZE - 1)
+ prefix_unmapped_sync(cur);
+ }
+}
+
+/*
+ * Map the first prefix page.
+ *
+ * The prefix will be protected, a gmap notifier will inform about unmaps.
+ * The shadow scb must not be executed until the prefix is remapped, this is
+ * guaranteed by properly handling PROG_REQUEST.
+ *
+ * Returns: - 0 on if successfully mapped or already mapped
+ * - > 0 if control has to be given to guest 2
+ * - -EAGAIN if the caller can retry immediately
+ * - -ENOMEM if out of memory
+ */
+static int map_prefix(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+ struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+ u64 prefix = scb_s->prefix << GUEST_PREFIX_SHIFT;
+ int rc;
+
+ /* mark it as mapped so we can catch any concurrent unmappers */
+ prefix_mapped(vsie_page);
+
+ /* with mso/msl, the prefix lies at offset *mso* */
+ prefix += scb_s->mso;
+
+ rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, prefix);
+ /*
+ * We don't have to mprotect, we will be called for all unshadows.
+ * SIE will detect if protection applies and trigger a validity.
+ */
+ if (rc)
+ prefix_unmapped(vsie_page);
+ if (rc > 0 || rc == -EFAULT)
+ rc = set_validity_icpt(scb_s, 0x0037U);
+ return rc;
+}
+
+/*
+ * Pin the guest page given by gpa and set hpa to the pinned host address.
+ * Will always be pinned writable.
+ *
+ * Returns: - 0 on success
+ * - -EINVAL if the gpa is not valid guest storage
+ * - -ENOMEM if out of memory
+ */
+static int pin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t *hpa)
+{
+ struct page *page;
+ hva_t hva;
+ int rc;
+
+ hva = gfn_to_hva(kvm, gpa_to_gfn(gpa));
+ if (kvm_is_error_hva(hva))
+ return -EINVAL;
+ rc = get_user_pages_fast(hva, 1, 1, &page);
+ if (rc < 0)
+ return rc;
+ else if (rc != 1)
+ return -ENOMEM;
+ *hpa = (hpa_t) page_to_virt(page) + (gpa & ~PAGE_MASK);
+ return 0;
+}
+
+/* Unpins a page previously pinned via pin_guest_page, marking it as dirty. */
+static void unpin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t hpa)
+{
+ struct page *page;
+
+ page = virt_to_page(hpa);
+ set_page_dirty_lock(page);
+ put_page(page);
+ /* mark the page always as dirty for migration */
+ mark_page_dirty(kvm, gpa_to_gfn(gpa));
+}
+
+/* unpin all blocks previously pinned by pin_blocks(), marking them dirty */
+static void unpin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+ struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+ struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+ hpa_t hpa;
+ gpa_t gpa;
+
+ hpa = (u64) scb_s->scaoh << 32 | scb_s->scaol;
+ if (hpa) {
+ gpa = scb_o->scaol & ~0xfUL;
+ unpin_guest_page(vcpu->kvm, gpa, hpa);
+ scb_s->scaol = 0;
+ scb_s->scaoh = 0;
+ }
+}
+
+/*
+ * Instead of shadowing some blocks, we can simply forward them because the
+ * addresses in the scb are 64 bit long.
+ *
+ * This works as long as the data lies in one page. If blocks ever exceed one
+ * page, we have to fall back to shadowing.
+ *
+ * As we reuse the sca, the vcpu pointers contained in it are invalid. We must
+ * therefore not enable any facilities that access these pointers (e.g. SIGPIF).
+ *
+ * Returns: - 0 if all blocks were pinned.
+ * - > 0 if control has to be given to guest 2
+ * - -ENOMEM if out of memory
+ */
+static int pin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+ struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+ struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+ hpa_t hpa;
+ gpa_t gpa;
+ int rc = 0;
+
+ gpa = scb_o->scaol & ~0xfUL;
+ if (gpa) {
+ if (!(gpa & ~0x1fffUL))
+ rc = set_validity_icpt(scb_s, 0x0038U);
+ else if ((gpa & ~0x1fffUL) == kvm_s390_get_prefix(vcpu))
+ rc = set_validity_icpt(scb_s, 0x0011U);
+ else if ((gpa & PAGE_MASK) !=
+ ((gpa + sizeof(struct bsca_block) - 1) & PAGE_MASK))
+ rc = set_validity_icpt(scb_s, 0x003bU);
+ if (!rc) {
+ rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
+ if (rc == -EINVAL)
+ rc = set_validity_icpt(scb_s, 0x0034U);
+ }
+ if (rc)
+ goto unpin;
+ scb_s->scaoh = (u32)((u64)hpa >> 32);
+ scb_s->scaol = (u32)(u64)hpa;
+ }
+ return 0;
+unpin:
+ unpin_blocks(vcpu, vsie_page);
+ return rc;
+}
+
+/* unpin the scb provided by guest 2, marking it as dirty */
+static void unpin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
+ gpa_t gpa)
+{
+ hpa_t hpa = (hpa_t) vsie_page->scb_o;
+
+ if (hpa)
+ unpin_guest_page(vcpu->kvm, gpa, hpa);
+ vsie_page->scb_o = NULL;
+}
+
+/*
+ * Pin the scb at gpa provided by guest 2 at vsie_page->scb_o.
+ *
+ * Returns: - 0 if the scb was pinned.
+ * - > 0 if control has to be given to guest 2
+ * - -ENOMEM if out of memory
+ */
+static int pin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
+ gpa_t gpa)
+{
+ hpa_t hpa;
+ int rc;
+
+ rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
+ if (rc == -EINVAL) {
+ rc = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+ if (!rc)
+ rc = 1;
+ }
+ if (!rc)
+ vsie_page->scb_o = (struct kvm_s390_sie_block *) hpa;
+ return rc;
+}
+
+/*
+ * Inject a fault into guest 2.
+ *
+ * Returns: - > 0 if control has to be given to guest 2
+ * < 0 if an error occurred during injection.
+ */
+static int inject_fault(struct kvm_vcpu *vcpu, __u16 code, __u64 vaddr,
+ bool write_flag)
+{
+ struct kvm_s390_pgm_info pgm = {
+ .code = code,
+ .trans_exc_code =
+ /* 0-51: virtual address */
+ (vaddr & 0xfffffffffffff000UL) |
+ /* 52-53: store / fetch */
+ (((unsigned int) !write_flag) + 1) << 10,
+ /* 62-63: asce id (alway primary == 0) */
+ .exc_access_id = 0, /* always primary */
+ .op_access_id = 0, /* not MVPG */
+ };
+ int rc;
+
+ if (code == PGM_PROTECTION)
+ pgm.trans_exc_code |= 0x4UL;
+
+ rc = kvm_s390_inject_prog_irq(vcpu, &pgm);
+ return rc ? rc : 1;
+}
+
+/*
+ * Handle a fault during vsie execution on a gmap shadow.
+ *
+ * Returns: - 0 if the fault was resolved
+ * - > 0 if control has to be given to guest 2
+ * - < 0 if an error occurred
+ */
+static int handle_fault(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+ int rc;
+
+ if (current->thread.gmap_int_code == PGM_PROTECTION)
+ /* we can directly forward all protection exceptions */
+ return inject_fault(vcpu, PGM_PROTECTION,
+ current->thread.gmap_addr, 1);
+
+ rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
+ current->thread.gmap_addr);
+ if (rc > 0) {
+ rc = inject_fault(vcpu, rc,
+ current->thread.gmap_addr,
+ current->thread.gmap_write_flag);
+ }
+ return rc;
+}
+
+static inline void clear_vsie_icpt(struct vsie_page *vsie_page)
+{
+ vsie_page->scb_s.icptcode = 0;
+}
+
+/*
+ * Run the vsie on a shadow scb and a shadow gmap, without any further
+ * sanity checks, handling SIE faults.
+ *
+ * Returns: - 0 everything went fine
+ * - > 0 if control has to be given to guest 2
+ * - < 0 if an error occurred
+ */
+static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+ struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+ struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+ int rc;
+
+ if (need_resched())
+ schedule();
+ if (test_cpu_flag(CIF_MCCK_PENDING))
+ s390_handle_mcck();
+
+ srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+ local_irq_disable();
+ kvm_guest_enter();
+ local_irq_enable();
+
+ rc = sie64a(scb_s, vcpu->run->s.regs.gprs);
+
+ local_irq_disable();
+ kvm_guest_exit();
+ local_irq_enable();
+ vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+
+ if (rc > 0)
+ rc = 0; /* we could still have an icpt */
+ else if (rc == -EFAULT)
+ return handle_fault(vcpu, vsie_page);
+
+ switch (scb_s->icptcode) {
+ case ICPT_STOP:
+ /* stop not requested by g2 - must have been a kick */
+ if (!(atomic_read(&scb_o->cpuflags) & CPUSTAT_STOP_INT))
+ clear_vsie_icpt(vsie_page);
+ break;
+ case ICPT_VALIDITY:
+ if ((scb_s->ipa & 0xf000) != 0xf000)
+ scb_s->ipa += 0x1000;
+ break;
+ }
+ return rc;
+}
+
+static void release_gmap_shadow(struct vsie_page *vsie_page)
+{
+ if (vsie_page->gmap)
+ gmap_put(vsie_page->gmap);
+ WRITE_ONCE(vsie_page->gmap, NULL);
+}
+
+static int acquire_gmap_shadow(struct kvm_vcpu *vcpu,
+ struct vsie_page *vsie_page)
+{
+ unsigned long asce;
+ union ctlreg0 cr0;
+ struct gmap *gmap;
+ int edat;
+
+ asce = vcpu->arch.sie_block->gcr[1];
+ cr0.val = vcpu->arch.sie_block->gcr[0];
+ edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8);
+ edat += edat && test_kvm_facility(vcpu->kvm, 78);
+
+ gmap = gmap_shadow(vcpu->arch.gmap, asce, edat);
+ if (IS_ERR(gmap))
+ return PTR_ERR(gmap);
+ gmap->private = vcpu->kvm;
+ WRITE_ONCE(vsie_page->gmap, gmap);
+ return 0;
+}
+
+/*
+ * Run the vsie on a shadowed scb, managing the gmap shadow, handling
+ * prefix pages and faults.
+ *
+ * Returns: - 0 if no errors occurred
+ * - > 0 if control has to be given to guest 2
+ * - -ENOMEM if out of memory
+ */
+static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+ struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+ int rc = 0;
+
+ while (1) {
+ rc = acquire_gmap_shadow(vcpu, vsie_page);
+ if (!rc)
+ rc = map_prefix(vcpu, vsie_page);
+ if (!rc) {
+ gmap_enable(vsie_page->gmap);
+ update_intervention_requests(vsie_page);
+ rc = do_vsie_run(vcpu, vsie_page);
+ gmap_enable(vcpu->arch.gmap);
+ }
+ release_gmap_shadow(vsie_page);
+
+ if (rc == -EAGAIN)
+ rc = 0;
+ if (rc || scb_s->icptcode || signal_pending(current) ||
+ kvm_s390_vcpu_has_irq(vcpu, 0))
+ break;
+ };
+
+ if (rc == -EFAULT) {
+ /*
+ * Addressing exceptions are always presentes as intercepts.
+ * As addressing exceptions are suppressing and our guest 3 PSW
+ * points at the responsible instruction, we have to
+ * forward the PSW and set the ilc. If we can't read guest 3
+ * instruction, we can use an arbitrary ilc. Let's always use
+ * ilen = 4 for now, so we can avoid reading in guest 3 virtual
+ * memory. (we could also fake the shadow so the hardware
+ * handles it).
+ */
+ scb_s->icptcode = ICPT_PROGI;
+ scb_s->iprcc = PGM_ADDRESSING;
+ scb_s->pgmilc = 4;
+ scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, 4);
+ }
+ return rc;
+}
+
+/*
+ * Get or create a vsie page for a scb address.
+ *
+ * Returns: - address of a vsie page (cached or new one)
+ * - NULL if the same scb address is already used by another VCPU
+ * - ERR_PTR(-ENOMEM) if out of memory
+ */
+static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr)
+{
+ struct vsie_page *vsie_page;
+ struct page *page;
+ int nr_vcpus;
+
+ rcu_read_lock();
+ page = radix_tree_lookup(&kvm->arch.vsie.addr_to_page, addr >> 9);
+ rcu_read_unlock();
+ if (page) {
+ if (page_ref_inc_return(page) == 2)
+ return page_to_virt(page);
+ page_ref_dec(page);
+ }
+
+ /*
+ * We want at least #online_vcpus shadows, so every VCPU can execute
+ * the VSIE in parallel.
+ */
+ nr_vcpus = atomic_read(&kvm->online_vcpus);
+
+ mutex_lock(&kvm->arch.vsie.mutex);
+ if (kvm->arch.vsie.page_count < nr_vcpus) {
+ page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+ if (!page) {
+ mutex_unlock(&kvm->arch.vsie.mutex);
+ return ERR_PTR(-ENOMEM);
+ }
+ page_ref_inc(page);
+ kvm->arch.vsie.pages[kvm->arch.vsie.page_count] = page;
+ kvm->arch.vsie.page_count++;
+ } else {
+ /* reuse an existing entry that belongs to nobody */
+ while (true) {
+ page = kvm->arch.vsie.pages[kvm->arch.vsie.next];
+ if (page_ref_inc_return(page) == 2)
+ break;
+ page_ref_dec(page);
+ kvm->arch.vsie.next++;
+ kvm->arch.vsie.next %= nr_vcpus;
+ }
+ radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9);
+ }
+ page->index = addr;
+ /* double use of the same address */
+ if (radix_tree_insert(&kvm->arch.vsie.addr_to_page, addr >> 9, page)) {
+ page_ref_dec(page);
+ mutex_unlock(&kvm->arch.vsie.mutex);
+ return NULL;
+ }
+ mutex_unlock(&kvm->arch.vsie.mutex);
+
+ vsie_page = page_to_virt(page);
+ memset(&vsie_page->scb_s, 0, sizeof(struct kvm_s390_sie_block));
+ vsie_page->scb_s.ihcpu = 0xffffU;
+ return vsie_page;
+}
+
+/* put a vsie page acquired via get_vsie_page */
+static void put_vsie_page(struct kvm *kvm, struct vsie_page *vsie_page)
+{
+ struct page *page = pfn_to_page(__pa(vsie_page) >> PAGE_SHIFT);
+
+ page_ref_dec(page);
+}
+
+int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu)
+{
+ struct vsie_page *vsie_page;
+ unsigned long scb_addr;
+ int rc;
+
+ vcpu->stat.instruction_sie++;
+ if (!test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIEF2))
+ return -EOPNOTSUPP;
+ if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
+ return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
+
+ BUILD_BUG_ON(sizeof(struct vsie_page) != 4096);
+ scb_addr = kvm_s390_get_base_disp_s(vcpu, NULL);
+
+ /* 512 byte alignment */
+ if (unlikely(scb_addr & 0x1ffUL))
+ return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
+
+ if (signal_pending(current) || kvm_s390_vcpu_has_irq(vcpu, 0))
+ return 0;
+
+ vsie_page = get_vsie_page(vcpu->kvm, scb_addr);
+ if (IS_ERR(vsie_page))
+ return PTR_ERR(vsie_page);
+ else if (!vsie_page)
+ /* double use of sie control block - simply do nothing */
+ return 0;
+
+ rc = pin_scb(vcpu, vsie_page, scb_addr);
+ if (rc)
+ goto out_put;
+ rc = shadow_scb(vcpu, vsie_page);
+ if (rc)
+ goto out_unpin_scb;
+ rc = pin_blocks(vcpu, vsie_page);
+ if (rc)
+ goto out_unshadow;
+ rc = vsie_run(vcpu, vsie_page);
+ unpin_blocks(vcpu, vsie_page);
+out_unshadow:
+ unshadow_scb(vcpu, vsie_page);
+out_unpin_scb:
+ unpin_scb(vcpu, vsie_page, scb_addr);
+out_put:
+ put_vsie_page(vcpu->kvm, vsie_page);
+
+ return rc < 0 ? rc : 0;
+}
+
+/* Init the vsie data structures. To be called when a vm is initialized. */
+void kvm_s390_vsie_init(struct kvm *kvm)
+{
+ mutex_init(&kvm->arch.vsie.mutex);
+ INIT_RADIX_TREE(&kvm->arch.vsie.addr_to_page, GFP_KERNEL);
+}
+
+/* Destroy the vsie data structures. To be called when a vm is destroyed. */
+void kvm_s390_vsie_destroy(struct kvm *kvm)
+{
+ struct page *page;
+ int i;
+
+ mutex_lock(&kvm->arch.vsie.mutex);
+ for (i = 0; i < kvm->arch.vsie.page_count; i++) {
+ page = kvm->arch.vsie.pages[i];
+ kvm->arch.vsie.pages[i] = NULL;
+ /* free the radix tree entry */
+ radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9);
+ __free_page(page);
+ }
+ kvm->arch.vsie.page_count = 0;
+ mutex_unlock(&kvm->arch.vsie.mutex);
+}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.