KVM: s390: vsie: Allow CRYCB FORMAT-2

BugLink: https://bugs.launchpad.net/bugs/1787405
When the guest and the host both use CRYCB FORMAT-2,
we copy the guest's FORMAT-1 APCB to a FORMAT-1
shadow APCB.

This patch also cleans up the shadow_crycb() function.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Message-Id: <20180925231641.4954-19-akrowiak@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
(cherry picked from commit 56019f9aca2266edc7f304d91e4e772023b7aa14)
Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Acked-by: Kamal Mostafa <kamal@canonical.com>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index 1211ccaa30bf5b3fd79d0ee3ef23a6be3708b614..dc552f8be3293e73ccda058ae331354eccf46fb0 100644 (file)
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -130,14 +130,81 @@ static int prepare_cpuflags(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
        return 0;
 }
 
-/*
+/**
+ * setup_apcb11 - Copy the FORMAT1 APCB from the guest to the shadow CRYCB
+ * @vcpu: pointer to the virtual CPU
+ * @apcb_s: pointer to start of apcb in the shadow crycb
+ * @apcb_o: pointer to start of original guest apcb
+ * @apcb_h: pointer to start of apcb in the host
+ *
+ * Returns 0 and -EFAULT on error reading guest apcb
+ */
+static int setup_apcb11(struct kvm_vcpu *vcpu, unsigned long *apcb_s,
+                       unsigned long apcb_o,
+                       unsigned long *apcb_h)
+{
+       if (read_guest_real(vcpu, apcb_o, apcb_s,
+                           sizeof(struct kvm_s390_apcb1)))
+               return -EFAULT;
+
+       bitmap_and(apcb_s, apcb_s, apcb_h, sizeof(struct kvm_s390_apcb1));
+
+       return 0;
+}
+
+/**
+ * setup_apcb - Create a shadow copy of the apcb.
+ * @vcpu: pointer to the virtual CPU
+ * @crycb_s: pointer to shadow crycb
+ * @crycb_o: pointer to original guest crycb
+ * @crycb_h: pointer to the host crycb
+ * @fmt_o: format of the original guest crycb.
+ * @fmt_h: format of the host crycb.
+ *
+ * Checks the compatibility between the guest and host crycb and calls the
+ * appropriate copy function.
+ *
+ * Return 0 or an error number if the guest and host crycb are incompatible.
+ */
+static int setup_apcb(struct kvm_vcpu *vcpu, struct kvm_s390_crypto_cb *crycb_s,
+              const u32 crycb_o,
+              struct kvm_s390_crypto_cb *crycb_h,
+              int fmt_o, int fmt_h)
+{
+       struct kvm_s390_crypto_cb *crycb;
+
+       crycb = (struct kvm_s390_crypto_cb *) (unsigned long)crycb_o;
+
+       switch (fmt_o) {
+       case CRYCB_FORMAT2:
+               if ((crycb_o & PAGE_MASK) != ((crycb_o + 256) & PAGE_MASK))
+                       return -EACCES;
+               if (fmt_h != CRYCB_FORMAT2)
+                       return -EINVAL;
+               return setup_apcb11(vcpu, (unsigned long *)&crycb_s->apcb1,
+                                   (unsigned long) &crycb->apcb1,
+                                   (unsigned long *)&crycb_h->apcb1);
+       }
+       return -EINVAL;
+}
+
+/**
+ * shadow_crycb - Create a shadow copy of the crycb block
+ * @vcpu: a pointer to the virtual CPU
+ * @vsie_page: a pointer to internal date used for the vSIE
+ *
  * Create a shadow copy of the crycb block and setup key wrapping, if
  * requested for guest 3 and enabled for guest 2.
  *
- * We accept format-1 or format-2, but we treat it as a format-1 (no AP in g2),
- * and we convert it into format-2 in the shadow CRYCB.
+ * We accept format-1 or format-2, but we convert format-1 into format-2
+ * in the shadow CRYCB.
+ * Using format-2 enables the firmware to choose the right format when
+ * scheduling the SIE.
  * There is nothing to do for format-0.
  *
+ * This function centralize the issuing of set_validity_icpt() for all
+ * the subfunctions working on the crycb.
+ *
  * Returns: - 0 if shadowed or nothing to do
  *          - > 0 if control has to be given to guest 2
  */
@@ -149,31 +216,48 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
        const u32 crycb_addr = crycbd_o & 0x7ffffff8U;
        unsigned long *b1, *b2;
        u8 ecb3_flags;
+       int apie_h;
+       int key_msk = test_kvm_facility(vcpu->kvm, 76);
+       int fmt_o = crycbd_o & CRYCB_FORMAT_MASK;
+       int fmt_h = vcpu->arch.sie_block->crycbd & CRYCB_FORMAT_MASK;
+       int ret = 0;
 
        scb_s->crycbd = 0;
        if (!(crycbd_o & vcpu->arch.sie_block->crycbd & CRYCB_FORMAT1))
                return 0;
-       /* format-1 is supported with message-security-assist extension 3 */
-       if (!test_kvm_facility(vcpu->kvm, 76))
+
+       apie_h = vcpu->arch.sie_block->eca & ECA_APIE;
+       if (!apie_h && !key_msk)
                return 0;
 
-       if ((crycb_addr & PAGE_MASK) != ((crycb_addr + 128) & PAGE_MASK))
-               return set_validity_icpt(scb_s, 0x003CU);
-       else if (!crycb_addr)
+       if (!crycb_addr)
                return set_validity_icpt(scb_s, 0x0039U);
 
+       if (fmt_o == CRYCB_FORMAT1)
+               if ((crycb_addr & PAGE_MASK) !=
+                   ((crycb_addr + 128) & PAGE_MASK))
+                       return set_validity_icpt(scb_s, 0x003CU);
+
+       if (apie_h && (scb_o->eca & ECA_APIE)) {
+               ret = setup_apcb(vcpu, &vsie_page->crycb, crycb_addr,
+                                vcpu->kvm->arch.crypto.crycb,
+                                fmt_o, fmt_h);
+               if (ret)
+                       goto end;
+               scb_s->eca |= scb_o->eca & ECA_APIE;
+       }
+
        /* we may only allow it if enabled for guest 2 */
        ecb3_flags = scb_o->ecb3 & vcpu->arch.sie_block->ecb3 &
                     (ECB3_AES | ECB3_DEA);
        if (!ecb3_flags)
-               return 0;
+               goto end;
 
        /* copy only the wrapping keys */
        if (read_guest_real(vcpu, crycb_addr + 72, &vsie_page->crycb, 56))
                return set_validity_icpt(scb_s, 0x0035U);
 
        scb_s->ecb3 |= ecb3_flags;
-       scb_s->crycbd = ((__u32)(__u64) &vsie_page->crycb) | CRYCB_FORMAT2;
 
        /* xor both blocks in one run */
        b1 = (unsigned long *) vsie_page->crycb.dea_wrapping_key_mask;
@@ -181,6 +265,16 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
                            vcpu->kvm->arch.crypto.crycb->dea_wrapping_key_mask;
        /* as 56%8 == 0, bitmap_xor won't overwrite any data */
        bitmap_xor(b1, b1, b2, BITS_PER_BYTE * 56);
+end:
+       switch (ret) {
+       case -EINVAL:
+               return set_validity_icpt(scb_s, 0x0020U);
+       case -EFAULT:
+               return set_validity_icpt(scb_s, 0x0035U);
+       case -EACCES:
+               return set_validity_icpt(scb_s, 0x003CU);
+       }
+       scb_s->crycbd = ((__u32)(__u64) &vsie_page->crycb) | CRYCB_FORMAT2;
        return 0;
 }