Commit 70455a36 authored by Christian Borntraeger's avatar Christian Borntraeger Committed by Avi Kivity
Browse files

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: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 2c411b48

arch/s390/kvm/intercept.c

+1 −1
Original line number Diff line number Diff line
@@ -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,

};

arch/s390/kvm/kvm-s390.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

arch/s390/kvm/priv.c

+15 −3
Original line number Diff line number Diff line
@@ -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)

	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;

}