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[S390] kvm: handle tprot intercepts 

When running a kvm guest we can get intercepts for tprot, if the host
page table is read-only or not populated. This patch implements the
most common case (linux memory detection).
This also allows host copy on write for guest memory on newer systems.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Christian Borntraeger 2011-07-24 10:48:17 +02:00 committed by Martin Schwidefsky
parent b02f0c2ea2
commit bb25b9ba3e
5 changed files with 53 additions and 0 deletions
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1
arch/s390/include/asm/kvm_host.h
View File

@ -138,6 +138,7 @@ struct kvm_vcpu_stat {
u32 instruction_chsc;
u32 instruction_stsi;
u32 instruction_stfl;
u32 instruction_tprot;
u32 instruction_sigp_sense;
u32 instruction_sigp_emergency;
u32 instruction_sigp_stop;

1
arch/s390/kvm/intercept.c
View File

@ -105,6 +105,7 @@ static intercept_handler_t instruction_handlers[256] = {
[0xae] = kvm_s390_handle_sigp,
[0xb2] = kvm_s390_handle_b2,
[0xb7] = handle_lctl,
[0xe5] = kvm_s390_handle_e5,
[0xeb] = handle_lctlg,
};

1
arch/s390/kvm/kvm-s390.c
View File

@ -62,6 +62,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
{ "instruction_chsc", VCPU_STAT(instruction_chsc) },
{ "instruction_stsi", VCPU_STAT(instruction_stsi) },
{ "instruction_stfl", VCPU_STAT(instruction_stfl) },
{ "instruction_tprot", VCPU_STAT(instruction_tprot) },
{ "instruction_sigp_sense", VCPU_STAT(instruction_sigp_sense) },
{ "instruction_sigp_emergency", VCPU_STAT(instruction_sigp_emergency) },
{ "instruction_sigp_stop", VCPU_STAT(instruction_sigp_stop) },

1
arch/s390/kvm/kvm-s390.h
View File

@ -87,6 +87,7 @@ static inline void kvm_s390_vcpu_set_mem(struct kvm_vcpu *vcpu)
/* implemented in priv.c */
int kvm_s390_handle_b2(struct kvm_vcpu *vcpu);
int kvm_s390_handle_e5(struct kvm_vcpu *vcpu);
/* implemented in sigp.c */
int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu);

49
arch/s390/kvm/priv.c
View File

@ -326,3 +326,52 @@ int kvm_s390_handle_b2(struct kvm_vcpu *vcpu)
}
return -EOPNOTSUPP;
}
static int handle_tprot(struct kvm_vcpu *vcpu)
{
int base1 = (vcpu->arch.sie_block->ipb & 0xf0000000) >> 28;
int disp1 = (vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16;
int base2 = (vcpu->arch.sie_block->ipb & 0xf000) >> 12;
int disp2 = vcpu->arch.sie_block->ipb & 0x0fff;
u64 address1 = disp1 + base1 ? vcpu->arch.guest_gprs[base1] : 0;
u64 address2 = disp2 + base2 ? vcpu->arch.guest_gprs[base2] : 0;
struct vm_area_struct *vma;
vcpu->stat.instruction_tprot++;
/* we only handle the Linux memory detection case:
* access key == 0
* guest DAT == off
* everything else goes to userspace. */
if (address2 & 0xf0)
return -EOPNOTSUPP;
if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
return -EOPNOTSUPP;
down_read(&current->mm->mmap_sem);
vma = find_vma(current->mm,
(unsigned long) __guestaddr_to_user(vcpu, address1));
if (!vma) {
up_read(&current->mm->mmap_sem);
return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
}
vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
if (!(vma->vm_flags & VM_WRITE) && (vma->vm_flags & VM_READ))
vcpu->arch.sie_block->gpsw.mask |= (1ul << 44);
if (!(vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_READ))
vcpu->arch.sie_block->gpsw.mask |= (2ul << 44);
up_read(&current->mm->mmap_sem);
return 0;
}
int kvm_s390_handle_e5(struct kvm_vcpu *vcpu)
{
/* For e5xx... instructions we only handle TPROT */
if ((vcpu->arch.sie_block->ipa & 0x00ff) == 0x01)
return handle_tprot(vcpu);
return -EOPNOTSUPP;
}