* [PATCH v4 1/2] s390/kvm: extend kvm_s390_shadow_fault to return entry pointer
2021-02-23 19:13 [PATCH v4 0/2] s390/kvm: fix MVPG when in VSIE Claudio Imbrenda
@ 2021-02-23 19:13 ` Claudio Imbrenda
2021-02-23 19:13 ` [PATCH v4 2/2] s390/kvm: VSIE: correctly handle MVPG when in VSIE Claudio Imbrenda
2021-02-24 8:15 ` [PATCH v4 0/2] s390/kvm: fix " Janosch Frank
2 siblings, 0 replies; 5+ messages in thread
From: Claudio Imbrenda @ 2021-02-23 19:13 UTC (permalink / raw)
To: linux-kernel
Cc: borntraeger, frankja, david, cohuck, kvm, linux-s390, stable,
Janosch Frank
Extend kvm_s390_shadow_fault to return the pointer to the valid leaf
DAT table entry, or to the invalid entry.
Also return some flags in the lower bits of the address:
PEI_DAT_PROT: indicates that DAT protection applies because of the
protection bit in the segment (or, if EDAT, region) tables.
PEI_NOT_PTE: indicates that the address of the DAT table entry returned
does not refer to a PTE, but to a segment or region table.
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: stable@vger.kernel.org
Reviewed-by: Janosch Frank <frankja@de.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
---
arch/s390/kvm/gaccess.c | 30 +++++++++++++++++++++++++-----
arch/s390/kvm/gaccess.h | 6 +++++-
arch/s390/kvm/vsie.c | 8 ++++----
3 files changed, 34 insertions(+), 10 deletions(-)
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index 6d6b57059493..33a03e518640 100644
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -976,7 +976,9 @@ int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra)
* kvm_s390_shadow_tables - walk the guest page table and create shadow tables
* @sg: pointer to the shadow guest address space structure
* @saddr: faulting address in the shadow gmap
- * @pgt: pointer to the page table address result
+ * @pgt: pointer to the beginning of the page table for the given address if
+ * successful (return value 0), or to the first invalid DAT entry in
+ * case of exceptions (return value > 0)
* @fake: pgt references contiguous guest memory block, not a pgtable
*/
static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr,
@@ -1034,6 +1036,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr,
rfte.val = ptr;
goto shadow_r2t;
}
+ *pgt = ptr + vaddr.rfx * 8;
rc = gmap_read_table(parent, ptr + vaddr.rfx * 8, &rfte.val);
if (rc)
return rc;
@@ -1060,6 +1063,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr,
rste.val = ptr;
goto shadow_r3t;
}
+ *pgt = ptr + vaddr.rsx * 8;
rc = gmap_read_table(parent, ptr + vaddr.rsx * 8, &rste.val);
if (rc)
return rc;
@@ -1087,6 +1091,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr,
rtte.val = ptr;
goto shadow_sgt;
}
+ *pgt = ptr + vaddr.rtx * 8;
rc = gmap_read_table(parent, ptr + vaddr.rtx * 8, &rtte.val);
if (rc)
return rc;
@@ -1123,6 +1128,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr,
ste.val = ptr;
goto shadow_pgt;
}
+ *pgt = ptr + vaddr.sx * 8;
rc = gmap_read_table(parent, ptr + vaddr.sx * 8, &ste.val);
if (rc)
return rc;
@@ -1157,6 +1163,8 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr,
* @vcpu: virtual cpu
* @sg: pointer to the shadow guest address space structure
* @saddr: faulting address in the shadow gmap
+ * @datptr: will contain the address of the faulting DAT table entry, or of
+ * the valid leaf, plus some flags
*
* Returns: - 0 if the shadow fault was successfully resolved
* - > 0 (pgm exception code) on exceptions while faulting
@@ -1165,11 +1173,11 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr,
* - -ENOMEM if out of memory
*/
int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
- unsigned long saddr)
+ unsigned long saddr, unsigned long *datptr)
{
union vaddress vaddr;
union page_table_entry pte;
- unsigned long pgt;
+ unsigned long pgt = 0;
int dat_protection, fake;
int rc;
@@ -1191,8 +1199,20 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
pte.val = pgt + vaddr.px * PAGE_SIZE;
goto shadow_page;
}
- if (!rc)
- rc = gmap_read_table(sg->parent, pgt + vaddr.px * 8, &pte.val);
+
+ switch (rc) {
+ case PGM_SEGMENT_TRANSLATION:
+ case PGM_REGION_THIRD_TRANS:
+ case PGM_REGION_SECOND_TRANS:
+ case PGM_REGION_FIRST_TRANS:
+ pgt |= PEI_NOT_PTE;
+ break;
+ case 0:
+ pgt += vaddr.px * 8;
+ rc = gmap_read_table(sg->parent, pgt, &pte.val);
+ }
+ if (*datptr)
+ *datptr = pgt | dat_protection * PEI_DAT_PROT;
if (!rc && pte.i)
rc = PGM_PAGE_TRANSLATION;
if (!rc && pte.z)
diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
index f4c51756c462..41e99cea7e4b 100644
--- a/arch/s390/kvm/gaccess.h
+++ b/arch/s390/kvm/gaccess.h
@@ -359,7 +359,11 @@ void ipte_unlock(struct kvm_vcpu *vcpu);
int ipte_lock_held(struct kvm_vcpu *vcpu);
int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra);
+/* MVPG PEI indication bits */
+#define PEI_DAT_PROT 2
+#define PEI_NOT_PTE 4
+
int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *shadow,
- unsigned long saddr);
+ unsigned long saddr, unsigned long *datptr);
#endif /* __KVM_S390_GACCESS_H */
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index bd803e091918..78b604326016 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -620,10 +620,10 @@ static int map_prefix(struct kvm_vcpu *vcpu, struct vsie_page *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);
+ rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, prefix, NULL);
if (!rc && (scb_s->ecb & ECB_TE))
rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
- prefix + PAGE_SIZE);
+ prefix + PAGE_SIZE, NULL);
/*
* We don't have to mprotect, we will be called for all unshadows.
* SIE will detect if protection applies and trigger a validity.
@@ -914,7 +914,7 @@ static int handle_fault(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
current->thread.gmap_addr, 1);
rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
- current->thread.gmap_addr);
+ current->thread.gmap_addr, NULL);
if (rc > 0) {
rc = inject_fault(vcpu, rc,
current->thread.gmap_addr,
@@ -936,7 +936,7 @@ static void handle_last_fault(struct kvm_vcpu *vcpu,
{
if (vsie_page->fault_addr)
kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
- vsie_page->fault_addr);
+ vsie_page->fault_addr, NULL);
vsie_page->fault_addr = 0;
}
--
2.26.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v4 2/2] s390/kvm: VSIE: correctly handle MVPG when in VSIE
2021-02-23 19:13 [PATCH v4 0/2] s390/kvm: fix MVPG when in VSIE Claudio Imbrenda
2021-02-23 19:13 ` [PATCH v4 1/2] s390/kvm: extend kvm_s390_shadow_fault to return entry pointer Claudio Imbrenda
@ 2021-02-23 19:13 ` Claudio Imbrenda
2021-02-25 19:12 ` David Hildenbrand
2021-02-24 8:15 ` [PATCH v4 0/2] s390/kvm: fix " Janosch Frank
2 siblings, 1 reply; 5+ messages in thread
From: Claudio Imbrenda @ 2021-02-23 19:13 UTC (permalink / raw)
To: linux-kernel; +Cc: borntraeger, frankja, david, cohuck, kvm, linux-s390, stable
Correctly handle the MVPG instruction when issued by a VSIE guest.
Fixes: a3508fbe9dc6d ("KVM: s390: vsie: initial support for nested virtualization")
Cc: stable@vger.kernel.org
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
---
arch/s390/kvm/vsie.c | 93 +++++++++++++++++++++++++++++++++++++++++---
1 file changed, 88 insertions(+), 5 deletions(-)
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index 78b604326016..dbf4241bc2dc 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -417,11 +417,6 @@ static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
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)
@@ -983,6 +978,90 @@ static int handle_stfle(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
return 0;
}
+static u64 vsie_get_register(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, u8 reg)
+{
+ reg &= 0xf;
+ switch (reg) {
+ case 15:
+ return vsie_page->scb_s.gg15;
+ case 14:
+ return vsie_page->scb_s.gg14;
+ default:
+ return vcpu->run->s.regs.gprs[reg];
+ }
+}
+
+static int vsie_handle_mvpg(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+ struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+ unsigned long pei_dest, pei_src, src, dest, mask = PAGE_MASK;
+ u64 *pei_block = &vsie_page->scb_o->mcic;
+ int edat, rc_dest, rc_src;
+ union ctlreg0 cr0;
+
+ cr0.val = vcpu->arch.sie_block->gcr[0];
+ edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8);
+ if (psw_bits(scb_s->gpsw).eaba == PSW_BITS_AMODE_24BIT)
+ mask = 0xfff000;
+ else if (psw_bits(scb_s->gpsw).eaba == PSW_BITS_AMODE_31BIT)
+ mask = 0x7ffff000;
+
+ dest = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 16) & mask;
+ src = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 20) & mask;
+
+ rc_dest = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, dest, &pei_dest);
+ rc_src = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, src, &pei_src);
+ /*
+ * Either everything went well, or something non-critical went wrong
+ * e.g. beause of a race. In either case, simply retry.
+ */
+ if (rc_dest == -EAGAIN || rc_src == -EAGAIN || (!rc_dest && !rc_src)) {
+ retry_vsie_icpt(vsie_page);
+ return -EAGAIN;
+ }
+ /* Something more serious went wrong, propagate the error */
+ if (rc_dest < 0)
+ return rc_dest;
+ if (rc_src < 0)
+ return rc_src;
+
+ /* The only possible suppressing exception: just deliver it */
+ if (rc_dest == PGM_TRANSLATION_SPEC || rc_src == PGM_TRANSLATION_SPEC) {
+ clear_vsie_icpt(vsie_page);
+ rc_dest = kvm_s390_inject_program_int(vcpu, PGM_TRANSLATION_SPEC);
+ WARN_ON_ONCE(rc_dest);
+ return 1;
+ }
+
+ /*
+ * Forward the PEI intercept to the guest if it was a page fault, or
+ * also for segment and region table faults if EDAT applies.
+ */
+ if (edat) {
+ rc_dest = rc_dest == PGM_ASCE_TYPE ? rc_dest : 0;
+ rc_src = rc_src == PGM_ASCE_TYPE ? rc_src : 0;
+ } else {
+ rc_dest = rc_dest != PGM_PAGE_TRANSLATION ? rc_dest : 0;
+ rc_src = rc_src != PGM_PAGE_TRANSLATION ? rc_src : 0;
+ }
+ if (!rc_dest && !rc_src) {
+ pei_block[0] = pei_dest;
+ pei_block[1] = pei_src;
+ return 1;
+ }
+
+ retry_vsie_icpt(vsie_page);
+
+ /*
+ * The host has edat, and the guest does not, or it was an ASCE type
+ * exception. The host needs to inject the appropriate DAT interrupts
+ * into the guest.
+ */
+ if (rc_dest)
+ return inject_fault(vcpu, rc_dest, dest, 1);
+ return inject_fault(vcpu, rc_src, src, 0);
+}
+
/*
* Run the vsie on a shadow scb and a shadow gmap, without any further
* sanity checks, handling SIE faults.
@@ -1071,6 +1150,10 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
if ((scb_s->ipa & 0xf000) != 0xf000)
scb_s->ipa += 0x1000;
break;
+ case ICPT_PARTEXEC:
+ if (scb_s->ipa == 0xb254)
+ rc = vsie_handle_mvpg(vcpu, vsie_page);
+ break;
}
return rc;
}
--
2.26.2
^ permalink raw reply related [flat|nested] 5+ messages in thread