From: Janosch Frank <frankja@linux.ibm.com>
Subject: KVM: s390: Add skey emulation fault handling
Patch-mainline: v4.19-rc1
Git-commit: bd096f6443194e57382686a3ac5f2ce4e82b55d7
References: FATE#326372, LTC#169184, bsc#1113484
Summary: kernel: Introduce huge page KVM backing support
Description: This adds the KVM support for libhugetlbfs backings of
s390 KVM guests.
Upstream-Description:
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>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
arch/s390/kvm/kvm-s390.c | 15 +++++-
arch/s390/kvm/priv.c | 105 +++++++++++++++++++++++++++++++----------------
2 files changed, 83 insertions(+), 37 deletions(-)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1514,6 +1514,7 @@ static long kvm_s390_set_skeys(struct kv
uint8_t *keys;
uint64_t hva;
int srcu_idx, i, r = 0;
+ bool unlocked;
if (args->flags != 0)
return -EINVAL;
@@ -1538,9 +1539,11 @@ static long kvm_s390_set_skeys(struct kv
if (r)
goto out;
+ i = 0;
down_read(¤t->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;
@@ -1554,8 +1557,14 @@ static long kvm_s390_set_skeys(struct kv
}
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(¤t->mm->mmap_sem);
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -247,9 +247,10 @@ static int try_handle_skey(struct kvm_vc
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++;
@@ -263,18 +264,28 @@ static int handle_iske(struct kvm_vcpu *
kvm_s390_get_regs_rre(vcpu, ®1, ®2);
- 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(¤t->mm->mmap_sem);
- rc = get_guest_storage_key(current->mm, addr, &key);
- up_read(¤t->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(¤t->mm->mmap_sem);
+ goto retry;
+ }
+ }
if (rc)
return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+ up_read(¤t->mm->mmap_sem);
vcpu->run->s.regs.gprs[reg1] &= ~0xff;
vcpu->run->s.regs.gprs[reg1] |= key;
return 0;
@@ -282,8 +293,9 @@ static int handle_iske(struct kvm_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++;
@@ -297,19 +309,27 @@ static int handle_rrbe(struct kvm_vcpu *
kvm_s390_get_regs_rre(vcpu, ®1, ®2);
- 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(¤t->mm->mmap_sem);
- rc = reset_guest_reference_bit(current->mm, addr);
- up_read(¤t->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(¤t->mm->mmap_sem);
+ goto retry;
+ }
+ }
if (rc < 0)
return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
-
+ up_read(¤t->mm->mmap_sem);
kvm_s390_set_psw_cc(vcpu, rc);
return 0;
}
@@ -324,6 +344,7 @@ static int handle_sske(struct kvm_vcpu *
unsigned long start, end;
unsigned char key, oldkey;
int reg1, reg2;
+ bool unlocked;
int rc;
vcpu->stat.instruction_sske++;
@@ -356,19 +377,28 @@ static int handle_sske(struct kvm_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(¤t->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(¤t->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(¤t->mm->mmap_sem);
+ if (rc >= 0)
+ start += PAGE_SIZE;
}
if (m3 & (SSKE_MC | SSKE_MR)) {
@@ -944,15 +974,16 @@ static int handle_pfmf(struct kvm_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);
}
@@ -962,14 +993,20 @@ static int handle_pfmf(struct kvm_vcpu *
if (rc)
return rc;
down_read(¤t->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(¤t->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(¤t->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) {