From 19e1227768863a1469797c13ef8fea1af7beac2c Mon Sep 17 00:00:00 2001 From: Janosch Frank Date: Tue, 2 Apr 2019 09:21:06 +0200 Subject: KVM: S390: protvirt: Introduce instruction data area bounce buffer Now that we can't access guest memory anymore, we have a dedicated satellite block that's a bounce buffer for instruction data. We re-use the memop interface to copy the instruction data to / from userspace. This lets us re-use a lot of QEMU code which used that interface to make logical guest memory accesses which are not possible anymore in protected mode anyway. Signed-off-by: Janosch Frank Reviewed-by: Thomas Huth Reviewed-by: David Hildenbrand [borntraeger@de.ibm.com: patch merging, splitting, fixing] Signed-off-by: Christian Borntraeger --- arch/s390/kvm/pv.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'arch/s390/kvm/pv.c') diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c index 9840ee49e572..13a41533eacf 100644 --- a/arch/s390/kvm/pv.c +++ b/arch/s390/kvm/pv.c @@ -33,10 +33,18 @@ int kvm_s390_pv_destroy_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc) if (!cc) free_pages(vcpu->arch.pv.stor_base, get_order(uv_info.guest_cpu_stor_len)); + + free_page(sida_origin(vcpu->arch.sie_block)); vcpu->arch.sie_block->pv_handle_cpu = 0; vcpu->arch.sie_block->pv_handle_config = 0; memset(&vcpu->arch.pv, 0, sizeof(vcpu->arch.pv)); vcpu->arch.sie_block->sdf = 0; + /* + * The sidad field (for sdf == 2) is now the gbea field (for sdf == 0). + * Use the reset value of gbea to avoid leaking the kernel pointer of + * the just freed sida. + */ + vcpu->arch.sie_block->gbea = 1; kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu); return cc ? EIO : 0; @@ -64,6 +72,14 @@ int kvm_s390_pv_create_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc) uvcb.state_origin = (u64)vcpu->arch.sie_block; uvcb.stor_origin = (u64)vcpu->arch.pv.stor_base; + /* Alloc Secure Instruction Data Area Designation */ + vcpu->arch.sie_block->sidad = __get_free_page(GFP_KERNEL | __GFP_ZERO); + if (!vcpu->arch.sie_block->sidad) { + free_pages(vcpu->arch.pv.stor_base, + get_order(uv_info.guest_cpu_stor_len)); + return -ENOMEM; + } + cc = uv_call(0, (u64)&uvcb); *rc = uvcb.header.rc; *rrc = uvcb.header.rrc; -- cgit