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Violators will be prosecuted for from ; Thu, 24 Oct 2019 12:42:23 +0100 From: Janosch Frank Subject: [RFC 20/37] KVM: S390: protvirt: Introduce instruction data area bounce buffer Date: Thu, 24 Oct 2019 07:40:42 -0400 In-Reply-To: <20191024114059.102802-1-frankja@linux.ibm.com> References: <20191024114059.102802-1-frankja@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-Id: <20191024114059.102802-21-frankja@linux.ibm.com> Sender: linux-s390-owner@vger.kernel.org List-ID: To: kvm@vger.kernel.org Cc: linux-s390@vger.kernel.org, thuth@redhat.com, david@redhat.com, borntraeger@de.ibm.com, imbrenda@linux.ibm.com, mihajlov@linux.ibm.com, mimu@linux.ibm.com, cohuck@redhat.com, gor@linux.ibm.com, frankja@linux.ibm.com Now that we can't access guest memory anymore, we have a dedicated sattelite 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 --- arch/s390/include/asm/kvm_host.h | 5 ++++- arch/s390/kvm/kvm-s390.c | 31 +++++++++++++++++++++++++++++++ arch/s390/kvm/pv.c | 9 +++++++++ 3 files changed, 44 insertions(+), 1 deletion(-) diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 5deabf9734d9..2a8a1e21e1c3 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -308,7 +308,10 @@ struct kvm_s390_sie_block { #define CRYCB_FORMAT2 0x00000003 __u32 crycbd; /* 0x00fc */ __u64 gcr[16]; /* 0x0100 */ - __u64 gbea; /* 0x0180 */ + union { + __u64 gbea; /* 0x0180 */ + __u64 sidad; + }; __u8 reserved188[8]; /* 0x0188 */ __u64 sdnxo; /* 0x0190 */ __u8 reserved198[8]; /* 0x0198 */ diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 97d3a81e5074..6747cb6cf062 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -4416,6 +4416,13 @@ static long kvm_s390_guest_mem_op(struct kvm_vcpu *vcpu, if (mop->size > MEM_OP_MAX_SIZE) return -E2BIG; + /* Protected guests move instruction data over the satellite + * block which has its own size limit + */ + if (kvm_s390_pv_is_protected(vcpu->kvm) && + mop->size > ((vcpu->arch.sie_block->sidad & 0x0f) + 1) * PAGE_SIZE) + return -E2BIG; + if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) { tmpbuf = vmalloc(mop->size); if (!tmpbuf) @@ -4427,10 +4434,22 @@ static long kvm_s390_guest_mem_op(struct kvm_vcpu *vcpu, switch (mop->op) { case KVM_S390_MEMOP_LOGICAL_READ: if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) { + if (kvm_s390_pv_is_protected(vcpu->kvm)) { + r = 0; + break; + } r = check_gva_range(vcpu, mop->gaddr, mop->ar, mop->size, GACC_FETCH); break; } + if (kvm_s390_pv_is_protected(vcpu->kvm)) { + r = 0; + if (copy_to_user(uaddr, (void *)vcpu->arch.sie_block->sidad + + (mop->gaddr & ~PAGE_MASK), + mop->size)) + r = -EFAULT; + break; + } r = read_guest(vcpu, mop->gaddr, mop->ar, tmpbuf, mop->size); if (r == 0) { if (copy_to_user(uaddr, tmpbuf, mop->size)) @@ -4439,10 +4458,22 @@ static long kvm_s390_guest_mem_op(struct kvm_vcpu *vcpu, break; case KVM_S390_MEMOP_LOGICAL_WRITE: if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) { + if (kvm_s390_pv_is_protected(vcpu->kvm)) { + r = 0; + break; + } r = check_gva_range(vcpu, mop->gaddr, mop->ar, mop->size, GACC_STORE); break; } + if (kvm_s390_pv_is_protected(vcpu->kvm)) { + r = 0; + if (copy_from_user((void *)vcpu->arch.sie_block->sidad + + (mop->gaddr & ~PAGE_MASK), uaddr, + mop->size)) + r = -EFAULT; + break; + } if (copy_from_user(tmpbuf, uaddr, mop->size)) { r = -EFAULT; break; diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c index 383e660e2221..be7d558ab897 100644 --- a/arch/s390/kvm/pv.c +++ b/arch/s390/kvm/pv.c @@ -119,6 +119,7 @@ int kvm_s390_pv_destroy_cpu(struct kvm_vcpu *vcpu) free_pages(vcpu->arch.pv.stor_base, get_order(uv_info.guest_cpu_stor_len)); + free_page(vcpu->arch.sie_block->sidad); /* Clear cpu and vm handle */ memset(&vcpu->arch.sie_block->reserved10, 0, sizeof(vcpu->arch.sie_block->reserved10)); @@ -150,6 +151,14 @@ int kvm_s390_pv_create_cpu(struct kvm_vcpu *vcpu) 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; + } + rc = uv_call(0, (u64)&uvcb); VCPU_EVENT(vcpu, 3, "PROTVIRT CREATE VCPU: cpu %d handle %llx rc %x rrc %x", vcpu->vcpu_id, uvcb.cpu_handle, uvcb.header.rc, -- 2.20.1