KVM: s390: Add skey emulation fault handling

When doing skey emulation for huge guests, we now need to fault in
pmds, as we don't have PGSTES anymore to store them when we do not
have valid table entries.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 4cff5e31ca36ba9d61316122a6217bd1ef939d45..662f4d8046db2ff3bdeaa386daf0cd7c6b369235 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1551,6 +1551,7 @@ static long kvm_s390_set_skeys(struct kvm *kvm, struct kvm_s390_skeys *args)
        uint8_t *keys;
        uint64_t hva;
        int srcu_idx, i, r = 0;
+       bool unlocked;
 
        if (args->flags != 0)
                return -EINVAL;
@@ -1575,9 +1576,11 @@ static long kvm_s390_set_skeys(struct kvm *kvm, struct kvm_s390_skeys *args)
        if (r)
                goto out;
 
+       i = 0;
        down_read(&current->mm->mmap_sem);
        srcu_idx = srcu_read_lock(&kvm->srcu);
-       for (i = 0; i < args->count; i++) {
+        while (i < args->count) {
+               unlocked = false;
                hva = gfn_to_hva(kvm, args->start_gfn + i);
                if (kvm_is_error_hva(hva)) {
                        r = -EFAULT;
@@ -1591,8 +1594,14 @@ static long kvm_s390_set_skeys(struct kvm *kvm, struct kvm_s390_skeys *args)
                }
 
                r = set_guest_storage_key(current->mm, hva, keys[i], 0);
-               if (r)
-                       break;
+               if (r) {
+                       r = fixup_user_fault(current, current->mm, hva,
+                                            FAULT_FLAG_WRITE, &unlocked);
+                       if (r)
+                               break;
+               }
+               if (!r)
+                       i++;
        }
        srcu_read_unlock(&kvm->srcu, srcu_idx);
        up_read(&current->mm->mmap_sem);

diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index eb0eb60c7be6a26677f8ed20509aba88df6da337..cfc5a62329f607d6971bc1a18b23132fddbc6ca0 100644 (file)
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -246,9 +246,10 @@ static int try_handle_skey(struct kvm_vcpu *vcpu)
 
 static int handle_iske(struct kvm_vcpu *vcpu)
 {
-       unsigned long addr;
+       unsigned long gaddr, vmaddr;
        unsigned char key;
        int reg1, reg2;
+       bool unlocked;
        int rc;
 
        vcpu->stat.instruction_iske++;
@@ -262,18 +263,28 @@ static int handle_iske(struct kvm_vcpu *vcpu)
 
        kvm_s390_get_regs_rre(vcpu, &reg1, &reg2);
 
-       addr = vcpu->run->s.regs.gprs[reg2] & PAGE_MASK;
-       addr = kvm_s390_logical_to_effective(vcpu, addr);
-       addr = kvm_s390_real_to_abs(vcpu, addr);
-       addr = gfn_to_hva(vcpu->kvm, gpa_to_gfn(addr));
-       if (kvm_is_error_hva(addr))
+       gaddr = vcpu->run->s.regs.gprs[reg2] & PAGE_MASK;
+       gaddr = kvm_s390_logical_to_effective(vcpu, gaddr);
+       gaddr = kvm_s390_real_to_abs(vcpu, gaddr);
+       vmaddr = gfn_to_hva(vcpu->kvm, gpa_to_gfn(gaddr));
+       if (kvm_is_error_hva(vmaddr))
                return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
-
+retry:
+       unlocked = false;
        down_read(&current->mm->mmap_sem);
-       rc = get_guest_storage_key(current->mm, addr, &key);
-       up_read(&current->mm->mmap_sem);
+       rc = get_guest_storage_key(current->mm, vmaddr, &key);
+
+       if (rc) {
+               rc = fixup_user_fault(current, current->mm, vmaddr,
+                                     FAULT_FLAG_WRITE, &unlocked);
+               if (!rc) {
+                       up_read(&current->mm->mmap_sem);
+                       goto retry;
+               }
+       }
        if (rc)
                return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+       up_read(&current->mm->mmap_sem);
        vcpu->run->s.regs.gprs[reg1] &= ~0xff;
        vcpu->run->s.regs.gprs[reg1] |= key;
        return 0;
@@ -281,8 +292,9 @@ static int handle_iske(struct kvm_vcpu *vcpu)
 
 static int handle_rrbe(struct kvm_vcpu *vcpu)
 {
-       unsigned long addr;
+       unsigned long vmaddr, gaddr;
        int reg1, reg2;
+       bool unlocked;
        int rc;
 
        vcpu->stat.instruction_rrbe++;
@@ -296,19 +308,27 @@ static int handle_rrbe(struct kvm_vcpu *vcpu)
 
        kvm_s390_get_regs_rre(vcpu, &reg1, &reg2);
 
-       addr = vcpu->run->s.regs.gprs[reg2] & PAGE_MASK;
-       addr = kvm_s390_logical_to_effective(vcpu, addr);
-       addr = kvm_s390_real_to_abs(vcpu, addr);
-       addr = gfn_to_hva(vcpu->kvm, gpa_to_gfn(addr));
-       if (kvm_is_error_hva(addr))
+       gaddr = vcpu->run->s.regs.gprs[reg2] & PAGE_MASK;
+       gaddr = kvm_s390_logical_to_effective(vcpu, gaddr);
+       gaddr = kvm_s390_real_to_abs(vcpu, gaddr);
+       vmaddr = gfn_to_hva(vcpu->kvm, gpa_to_gfn(gaddr));
+       if (kvm_is_error_hva(vmaddr))
                return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
-
+retry:
+       unlocked = false;
        down_read(&current->mm->mmap_sem);
-       rc = reset_guest_reference_bit(current->mm, addr);
-       up_read(&current->mm->mmap_sem);
+       rc = reset_guest_reference_bit(current->mm, vmaddr);
+       if (rc < 0) {
+               rc = fixup_user_fault(current, current->mm, vmaddr,
+                                     FAULT_FLAG_WRITE, &unlocked);
+               if (!rc) {
+                       up_read(&current->mm->mmap_sem);
+                       goto retry;
+               }
+       }
        if (rc < 0)
                return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
-
+       up_read(&current->mm->mmap_sem);
        kvm_s390_set_psw_cc(vcpu, rc);
        return 0;
 }
@@ -323,6 +343,7 @@ static int handle_sske(struct kvm_vcpu *vcpu)
        unsigned long start, end;
        unsigned char key, oldkey;
        int reg1, reg2;
+       bool unlocked;
        int rc;
 
        vcpu->stat.instruction_sske++;
@@ -355,19 +376,28 @@ static int handle_sske(struct kvm_vcpu *vcpu)
        }
 
        while (start != end) {
-               unsigned long addr = gfn_to_hva(vcpu->kvm, gpa_to_gfn(start));
+               unsigned long vmaddr = gfn_to_hva(vcpu->kvm, gpa_to_gfn(start));
+               unlocked = false;
 
-               if (kvm_is_error_hva(addr))
+               if (kvm_is_error_hva(vmaddr))
                        return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 
                down_read(&current->mm->mmap_sem);
-               rc = cond_set_guest_storage_key(current->mm, addr, key, &oldkey,
+               rc = cond_set_guest_storage_key(current->mm, vmaddr, key, &oldkey,
                                                m3 & SSKE_NQ, m3 & SSKE_MR,
                                                m3 & SSKE_MC);
-               up_read(&current->mm->mmap_sem);
-               if (rc < 0)
+
+               if (rc < 0) {
+                       rc = fixup_user_fault(current, current->mm, vmaddr,
+                                             FAULT_FLAG_WRITE, &unlocked);
+                       rc = !rc ? -EAGAIN : rc;
+               }
+               if (rc == -EFAULT)
                        return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
-               start += PAGE_SIZE;
+
+               up_read(&current->mm->mmap_sem);
+               if (rc >= 0)
+                       start += PAGE_SIZE;
        }
 
        if (m3 & (SSKE_MC | SSKE_MR)) {
@@ -948,15 +978,16 @@ static int handle_pfmf(struct kvm_vcpu *vcpu)
        }
 
        while (start != end) {
-               unsigned long useraddr;
+               unsigned long vmaddr;
+               bool unlocked = false;
 
                /* Translate guest address to host address */
-               useraddr = gfn_to_hva(vcpu->kvm, gpa_to_gfn(start));
-               if (kvm_is_error_hva(useraddr))
+               vmaddr = gfn_to_hva(vcpu->kvm, gpa_to_gfn(start));
+               if (kvm_is_error_hva(vmaddr))
                        return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 
                if (vcpu->run->s.regs.gprs[reg1] & PFMF_CF) {
-                       if (clear_user((void __user *)useraddr, PAGE_SIZE))
+                       if (clear_user((void __user *)vmaddr, PAGE_SIZE))
                                return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
                }
 
@@ -966,14 +997,20 @@ static int handle_pfmf(struct kvm_vcpu *vcpu)
                        if (rc)
                                return rc;
                        down_read(&current->mm->mmap_sem);
-                       rc = cond_set_guest_storage_key(current->mm, useraddr,
+                       rc = cond_set_guest_storage_key(current->mm, vmaddr,
                                                        key, NULL, nq, mr, mc);
-                       up_read(&current->mm->mmap_sem);
-                       if (rc < 0)
+                       if (rc < 0) {
+                               rc = fixup_user_fault(current, current->mm, vmaddr,
+                                                     FAULT_FLAG_WRITE, &unlocked);
+                               rc = !rc ? -EAGAIN : rc;
+                       }
+                       if (rc == -EFAULT)
                                return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
-               }
 
-               start += PAGE_SIZE;
+                       up_read(&current->mm->mmap_sem);
+                       if (rc >= 0)
+                               start += PAGE_SIZE;
+               }
        }
        if (vcpu->run->s.regs.gprs[reg1] & PFMF_FSC) {
                if (psw_bits(vcpu->arch.sie_block->gpsw).eaba == PSW_BITS_AMODE_64BIT) {