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KVM: s390: Fix problem state check for b2 intercepts 

The kernel handles some priviledged instruction exits. While I was
unable to trigger such an exit from guest userspace, the code should
check for supervisor state before emulating a priviledged instruction.

I also renamed kvm_s390_handle_priv to kvm_s390_handle_b2. After all
there are non priviledged b2 instructions like stck (store clock).

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Christian Borntraeger 2009-01-22 10:28:29 +01:00 committed by Avi Kivity
parent 2c411b48af
commit 70455a36a0
3 changed files with 17 additions and 5 deletions
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2
arch/s390/kvm/intercept.c
View File

@ -103,7 +103,7 @@ static int handle_lctl(struct kvm_vcpu *vcpu)
static intercept_handler_t instruction_handlers[256] = {
[0x83] = kvm_s390_handle_diag,
[0xae] = kvm_s390_handle_sigp,
[0xb2] = kvm_s390_handle_priv,
[0xb2] = kvm_s390_handle_b2,
[0xb7] = handle_lctl,
[0xeb] = handle_lctlg,
};

2
arch/s390/kvm/kvm-s390.h
View File

@ -50,7 +50,7 @@ int kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu,
int kvm_s390_inject_program_int(struct kvm_vcpu *vcpu, u16 code);
/* implemented in priv.c */
int kvm_s390_handle_priv(struct kvm_vcpu *vcpu);
int kvm_s390_handle_b2(struct kvm_vcpu *vcpu);
/* implemented in sigp.c */
int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu);

18
arch/s390/kvm/priv.c
View File

@ -304,12 +304,24 @@ static intercept_handler_t priv_handlers[256] = {
[0xb1] = handle_stfl,
};
int kvm_s390_handle_priv(struct kvm_vcpu *vcpu)
int kvm_s390_handle_b2(struct kvm_vcpu *vcpu)
{
intercept_handler_t handler;
/*
* a lot of B2 instructions are priviledged. We first check for
* the priviledges ones, that we can handle in the kernel. If the
* kernel can handle this instruction, we check for the problem
* state bit and (a) handle the instruction or (b) send a code 2
* program check.
* Anything else goes to userspace.*/
handler = priv_handlers[vcpu->arch.sie_block->ipa & 0x00ff];
if (handler)
return handler(vcpu);
if (handler) {
if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
return kvm_s390_inject_program_int(vcpu,
PGM_PRIVILEGED_OPERATION);
else
return handler(vcpu);
}
return -ENOTSUPP;
}