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Commit bb25b9ba authored by Christian Borntraeger's avatar Christian Borntraeger Committed by Martin Schwidefsky
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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: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent b02f0c2e

arch/s390/include/asm/kvm_host.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -138,6 +138,7 @@ struct kvm_vcpu_stat { 
	u32 instruction_chsc;

	u32 instruction_chsc;

	u32 instruction_stsi;

	u32 instruction_stsi;

	u32 instruction_stfl;

	u32 instruction_stfl;

	u32 instruction_tprot;

	u32 instruction_sigp_sense;

	u32 instruction_sigp_sense;

	u32 instruction_sigp_emergency;

	u32 instruction_sigp_emergency;

	u32 instruction_sigp_stop;

	u32 instruction_sigp_stop;

arch/s390/kvm/intercept.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -105,6 +105,7 @@ static intercept_handler_t instruction_handlers[256] = { 
	[0xae] = kvm_s390_handle_sigp,

	[0xae] = kvm_s390_handle_sigp,

	[0xb2] = kvm_s390_handle_b2,

	[0xb2] = kvm_s390_handle_b2,

	[0xb7] = handle_lctl,

	[0xb7] = handle_lctl,

	[0xe5] = kvm_s390_handle_e5,

	[0xeb] = handle_lctlg,

	[0xeb] = handle_lctlg,

};

};

arch/s390/kvm/kvm-s390.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -62,6 +62,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { 
	{ "instruction_chsc", VCPU_STAT(instruction_chsc) },

	{ "instruction_chsc", VCPU_STAT(instruction_chsc) },

	{ "instruction_stsi", VCPU_STAT(instruction_stsi) },

	{ "instruction_stsi", VCPU_STAT(instruction_stsi) },

	{ "instruction_stfl", VCPU_STAT(instruction_stfl) },

	{ "instruction_stfl", VCPU_STAT(instruction_stfl) },

	{ "instruction_tprot", VCPU_STAT(instruction_tprot) },

	{ "instruction_sigp_sense", VCPU_STAT(instruction_sigp_sense) },

	{ "instruction_sigp_sense", VCPU_STAT(instruction_sigp_sense) },

	{ "instruction_sigp_emergency", VCPU_STAT(instruction_sigp_emergency) },

	{ "instruction_sigp_emergency", VCPU_STAT(instruction_sigp_emergency) },

	{ "instruction_sigp_stop", VCPU_STAT(instruction_sigp_stop) },

	{ "instruction_sigp_stop", VCPU_STAT(instruction_sigp_stop) },

arch/s390/kvm/kvm-s390.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -87,6 +87,7 @@ static inline void kvm_s390_vcpu_set_mem(struct kvm_vcpu *vcpu) 




/* implemented in priv.c */

/* implemented in priv.c */

int kvm_s390_handle_b2(struct kvm_vcpu *vcpu);

int kvm_s390_handle_b2(struct kvm_vcpu *vcpu);

int kvm_s390_handle_e5(struct kvm_vcpu *vcpu);





/* implemented in sigp.c */

/* implemented in sigp.c */

int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu);

int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu);

arch/s390/kvm/priv.c

+49 −0
Original line number Original line Diff line number Diff line
@@ -326,3 +326,52 @@ int kvm_s390_handle_b2(struct kvm_vcpu *vcpu) 
	}

	}

	return -EOPNOTSUPP;

	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;

}