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author | Paolo Bonzini <pbonzini@redhat.com> | 2021-12-21 12:59:53 -0500 |
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committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-12-21 12:59:53 -0500 |
commit | 5e4e84f1124aa02643833b7ea40abd5a8e964388 (patch) | |
tree | e9fd709bc454be266c1935fa06652e01caf693d8 /arch/s390/kvm | |
parent | 855fb0384a3db2ae33b42f7b9bb6ecb753a40880 (diff) | |
parent | 812de04661c4daa7ac385c0dfd62594540538034 (diff) | |
download | linux-5e4e84f1124aa02643833b7ea40abd5a8e964388.tar.gz linux-5e4e84f1124aa02643833b7ea40abd5a8e964388.tar.bz2 linux-5e4e84f1124aa02643833b7ea40abd5a8e964388.zip |
Merge tag 'kvm-s390-next-5.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD
KVM: s390: Fix and cleanup
- fix sigp sense/start/stop/inconsistency
- cleanups
Diffstat (limited to 'arch/s390/kvm')
-rw-r--r-- | arch/s390/kvm/gaccess.c | 158 | ||||
-rw-r--r-- | arch/s390/kvm/interrupt.c | 7 | ||||
-rw-r--r-- | arch/s390/kvm/kvm-s390.c | 9 | ||||
-rw-r--r-- | arch/s390/kvm/kvm-s390.h | 1 | ||||
-rw-r--r-- | arch/s390/kvm/sigp.c | 28 |
5 files changed, 135 insertions, 68 deletions
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c index 6af59c59cc1b..4460808c3b9a 100644 --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -794,46 +794,100 @@ static int low_address_protection_enabled(struct kvm_vcpu *vcpu, return 1; } -static int guest_page_range(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, - unsigned long *pages, unsigned long nr_pages, - const union asce asce, enum gacc_mode mode) +/** + * guest_range_to_gpas() - Calculate guest physical addresses of page fragments + * covering a logical range + * @vcpu: virtual cpu + * @ga: guest address, start of range + * @ar: access register + * @gpas: output argument, may be NULL + * @len: length of range in bytes + * @asce: address-space-control element to use for translation + * @mode: access mode + * + * Translate a logical range to a series of guest absolute addresses, + * such that the concatenation of page fragments starting at each gpa make up + * the whole range. + * The translation is performed as if done by the cpu for the given @asce, @ar, + * @mode and state of the @vcpu. + * If the translation causes an exception, its program interruption code is + * returned and the &struct kvm_s390_pgm_info pgm member of @vcpu is modified + * such that a subsequent call to kvm_s390_inject_prog_vcpu() will inject + * a correct exception into the guest. + * The resulting gpas are stored into @gpas, unless it is NULL. + * + * Note: All fragments except the first one start at the beginning of a page. + * When deriving the boundaries of a fragment from a gpa, all but the last + * fragment end at the end of the page. + * + * Return: + * * 0 - success + * * <0 - translation could not be performed, for example if guest + * memory could not be accessed + * * >0 - an access exception occurred. In this case the returned value + * is the program interruption code and the contents of pgm may + * be used to inject an exception into the guest. + */ +static int guest_range_to_gpas(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, + unsigned long *gpas, unsigned long len, + const union asce asce, enum gacc_mode mode) { psw_t *psw = &vcpu->arch.sie_block->gpsw; + unsigned int offset = offset_in_page(ga); + unsigned int fragment_len; int lap_enabled, rc = 0; enum prot_type prot; + unsigned long gpa; lap_enabled = low_address_protection_enabled(vcpu, asce); - while (nr_pages) { + while (min(PAGE_SIZE - offset, len) > 0) { + fragment_len = min(PAGE_SIZE - offset, len); ga = kvm_s390_logical_to_effective(vcpu, ga); if (mode == GACC_STORE && lap_enabled && is_low_address(ga)) return trans_exc(vcpu, PGM_PROTECTION, ga, ar, mode, PROT_TYPE_LA); - ga &= PAGE_MASK; if (psw_bits(*psw).dat) { - rc = guest_translate(vcpu, ga, pages, asce, mode, &prot); + rc = guest_translate(vcpu, ga, &gpa, asce, mode, &prot); if (rc < 0) return rc; } else { - *pages = kvm_s390_real_to_abs(vcpu, ga); - if (kvm_is_error_gpa(vcpu->kvm, *pages)) + gpa = kvm_s390_real_to_abs(vcpu, ga); + if (kvm_is_error_gpa(vcpu->kvm, gpa)) rc = PGM_ADDRESSING; } if (rc) return trans_exc(vcpu, rc, ga, ar, mode, prot); - ga += PAGE_SIZE; - pages++; - nr_pages--; + if (gpas) + *gpas++ = gpa; + offset = 0; + ga += fragment_len; + len -= fragment_len; } return 0; } +static int access_guest_page(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa, + void *data, unsigned int len) +{ + const unsigned int offset = offset_in_page(gpa); + const gfn_t gfn = gpa_to_gfn(gpa); + int rc; + + if (mode == GACC_STORE) + rc = kvm_write_guest_page(kvm, gfn, data, offset, len); + else + rc = kvm_read_guest_page(kvm, gfn, data, offset, len); + return rc; +} + int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data, unsigned long len, enum gacc_mode mode) { psw_t *psw = &vcpu->arch.sie_block->gpsw; - unsigned long _len, nr_pages, gpa, idx; - unsigned long pages_array[2]; - unsigned long *pages; + unsigned long nr_pages, idx; + unsigned long gpa_array[2]; + unsigned int fragment_len; + unsigned long *gpas; int need_ipte_lock; union asce asce; int rc; @@ -845,49 +899,42 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data, if (rc) return rc; nr_pages = (((ga & ~PAGE_MASK) + len - 1) >> PAGE_SHIFT) + 1; - pages = pages_array; - if (nr_pages > ARRAY_SIZE(pages_array)) - pages = vmalloc(array_size(nr_pages, sizeof(unsigned long))); - if (!pages) + gpas = gpa_array; + if (nr_pages > ARRAY_SIZE(gpa_array)) + gpas = vmalloc(array_size(nr_pages, sizeof(unsigned long))); + if (!gpas) return -ENOMEM; need_ipte_lock = psw_bits(*psw).dat && !asce.r; if (need_ipte_lock) ipte_lock(vcpu); - rc = guest_page_range(vcpu, ga, ar, pages, nr_pages, asce, mode); + rc = guest_range_to_gpas(vcpu, ga, ar, gpas, len, asce, mode); for (idx = 0; idx < nr_pages && !rc; idx++) { - gpa = *(pages + idx) + (ga & ~PAGE_MASK); - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); - if (mode == GACC_STORE) - rc = kvm_write_guest(vcpu->kvm, gpa, data, _len); - else - rc = kvm_read_guest(vcpu->kvm, gpa, data, _len); - len -= _len; - ga += _len; - data += _len; + fragment_len = min(PAGE_SIZE - offset_in_page(gpas[idx]), len); + rc = access_guest_page(vcpu->kvm, mode, gpas[idx], data, fragment_len); + len -= fragment_len; + data += fragment_len; } if (need_ipte_lock) ipte_unlock(vcpu); - if (nr_pages > ARRAY_SIZE(pages_array)) - vfree(pages); + if (nr_pages > ARRAY_SIZE(gpa_array)) + vfree(gpas); return rc; } int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data, unsigned long len, enum gacc_mode mode) { - unsigned long _len, gpa; + unsigned int fragment_len; + unsigned long gpa; int rc = 0; while (len && !rc) { gpa = kvm_s390_real_to_abs(vcpu, gra); - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); - if (mode) - rc = write_guest_abs(vcpu, gpa, data, _len); - else - rc = read_guest_abs(vcpu, gpa, data, _len); - len -= _len; - gra += _len; - data += _len; + fragment_len = min(PAGE_SIZE - offset_in_page(gpa), len); + rc = access_guest_page(vcpu->kvm, mode, gpa, data, fragment_len); + len -= fragment_len; + gra += fragment_len; + data += fragment_len; } return rc; } @@ -909,8 +956,6 @@ int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar, unsigned long *gpa, enum gacc_mode mode) { - psw_t *psw = &vcpu->arch.sie_block->gpsw; - enum prot_type prot; union asce asce; int rc; @@ -918,23 +963,7 @@ int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar, rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode); if (rc) return rc; - if (is_low_address(gva) && low_address_protection_enabled(vcpu, asce)) { - if (mode == GACC_STORE) - return trans_exc(vcpu, PGM_PROTECTION, gva, 0, - mode, PROT_TYPE_LA); - } - - if (psw_bits(*psw).dat && !asce.r) { /* Use DAT? */ - rc = guest_translate(vcpu, gva, gpa, asce, mode, &prot); - if (rc > 0) - return trans_exc(vcpu, rc, gva, 0, mode, prot); - } else { - *gpa = kvm_s390_real_to_abs(vcpu, gva); - if (kvm_is_error_gpa(vcpu->kvm, *gpa)) - return trans_exc(vcpu, rc, gva, PGM_ADDRESSING, mode, 0); - } - - return rc; + return guest_range_to_gpas(vcpu, gva, ar, gpa, 1, asce, mode); } /** @@ -948,17 +977,14 @@ int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar, int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar, unsigned long length, enum gacc_mode mode) { - unsigned long gpa; - unsigned long currlen; + union asce asce; int rc = 0; + rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode); + if (rc) + return rc; ipte_lock(vcpu); - while (length > 0 && !rc) { - currlen = min(length, PAGE_SIZE - (gva % PAGE_SIZE)); - rc = guest_translate_address(vcpu, gva, ar, &gpa, mode); - gva += currlen; - length -= currlen; - } + rc = guest_range_to_gpas(vcpu, gva, ar, NULL, length, asce, mode); ipte_unlock(vcpu); return rc; diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index dbabd6f2404e..db933c252dbc 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -2116,6 +2116,13 @@ int kvm_s390_is_stop_irq_pending(struct kvm_vcpu *vcpu) return test_bit(IRQ_PEND_SIGP_STOP, &li->pending_irqs); } +int kvm_s390_is_restart_irq_pending(struct kvm_vcpu *vcpu) +{ + struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int; + + return test_bit(IRQ_PEND_RESTART, &li->pending_irqs); +} + void kvm_s390_clear_stop_irq(struct kvm_vcpu *vcpu) { struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int; diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index dd099d352753..9c6d45d0d345 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -4599,10 +4599,15 @@ int kvm_s390_vcpu_stop(struct kvm_vcpu *vcpu) } } - /* SIGP STOP and SIGP STOP AND STORE STATUS has been fully processed */ + /* + * Set the VCPU to STOPPED and THEN clear the interrupt flag, + * now that the SIGP STOP and SIGP STOP AND STORE STATUS orders + * have been fully processed. This will ensure that the VCPU + * is kept BUSY if another VCPU is inquiring with SIGP SENSE. + */ + kvm_s390_set_cpuflags(vcpu, CPUSTAT_STOPPED); kvm_s390_clear_stop_irq(vcpu); - kvm_s390_set_cpuflags(vcpu, CPUSTAT_STOPPED); __disable_ibs_on_vcpu(vcpu); for (i = 0; i < online_vcpus; i++) { diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h index 60f0effcce99..098831e815e6 100644 --- a/arch/s390/kvm/kvm-s390.h +++ b/arch/s390/kvm/kvm-s390.h @@ -441,6 +441,7 @@ void kvm_s390_destroy_adapters(struct kvm *kvm); int kvm_s390_ext_call_pending(struct kvm_vcpu *vcpu); extern struct kvm_device_ops kvm_flic_ops; int kvm_s390_is_stop_irq_pending(struct kvm_vcpu *vcpu); +int kvm_s390_is_restart_irq_pending(struct kvm_vcpu *vcpu); void kvm_s390_clear_stop_irq(struct kvm_vcpu *vcpu); int kvm_s390_set_irq_state(struct kvm_vcpu *vcpu, void __user *buf, int len); diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c index cf4de80bd541..8aaee2892ec3 100644 --- a/arch/s390/kvm/sigp.c +++ b/arch/s390/kvm/sigp.c @@ -276,6 +276,34 @@ static int handle_sigp_dst(struct kvm_vcpu *vcpu, u8 order_code, if (!dst_vcpu) return SIGP_CC_NOT_OPERATIONAL; + /* + * SIGP RESTART, SIGP STOP, and SIGP STOP AND STORE STATUS orders + * are processed asynchronously. Until the affected VCPU finishes + * its work and calls back into KVM to clear the (RESTART or STOP) + * interrupt, we need to return any new non-reset orders "busy". + * + * This is important because a single VCPU could issue: + * 1) SIGP STOP $DESTINATION + * 2) SIGP SENSE $DESTINATION + * + * If the SIGP SENSE would not be rejected as "busy", it could + * return an incorrect answer as to whether the VCPU is STOPPED + * or OPERATING. + */ + if (order_code != SIGP_INITIAL_CPU_RESET && + order_code != SIGP_CPU_RESET) { + /* + * Lockless check. Both SIGP STOP and SIGP (RE)START + * properly synchronize everything while processing + * their orders, while the guest cannot observe a + * difference when issuing other orders from two + * different VCPUs. + */ + if (kvm_s390_is_stop_irq_pending(dst_vcpu) || + kvm_s390_is_restart_irq_pending(dst_vcpu)) + return SIGP_CC_BUSY; + } + switch (order_code) { case SIGP_SENSE: vcpu->stat.instruction_sigp_sense++; |