From: Janosch Frank <frankja@xxxxxxxxxxxxx>
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 <frankja@xxxxxxxxxxxxx>
---
arch/s390/include/asm/kvm_host.h | 11 ++++++-
arch/s390/kvm/kvm-s390.c | 49 ++++++++++++++++++++++++++++++++
arch/s390/kvm/pv.c | 9 ++++++
include/uapi/linux/kvm.h | 11 +++++--
4 files changed, 77 insertions(+), 3 deletions(-)
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 125511ec6eb0..48f382680755 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -127,6 +127,12 @@ struct mcck_volatile_info {
#define CR14_INITIAL_MASK (CR14_UNUSED_32 | CR14_UNUSED_33 | \
CR14_EXTERNAL_DAMAGE_SUBMASK)
+#define SIDAD_SIZE_MASK 0xff
+#define sida_origin(sie_block) \
+ (sie_block->sidad & PAGE_MASK)
+#define sida_size(sie_block) \
+ (((sie_block->sidad & SIDAD_SIZE_MASK) + 1) * PAGE_SIZE)
+
#define CPUSTAT_STOPPED 0x80000000
#define CPUSTAT_WAIT 0x10000000
#define CPUSTAT_ECALL_PEND 0x08000000
@@ -315,7 +321,10 @@ 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 1945180b857a..76303b0f1226 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -4441,6 +4441,8 @@ static long kvm_s390_guest_mem_op(struct kvm_vcpu *vcpu,
const u64 supported_flags = KVM_S390_MEMOP_F_INJECT_EXCEPTION
| KVM_S390_MEMOP_F_CHECK_ONLY;
+
+ BUILD_BUG_ON(sizeof(*mop) != 64);
if (mop->flags & ~supported_flags || mop->ar >= NUM_ACRS || !mop->size)
return -EINVAL;
@@ -4522,6 +4524,39 @@ long kvm_arch_vcpu_async_ioctl(struct file *filp,
}
#ifdef CONFIG_KVM_S390_PROTECTED_VIRTUALIZATION_HOST
+static long kvm_s390_guest_sida_op(struct kvm_vcpu *vcpu,
+ struct kvm_s390_mem_op *mop)
+{
+ int r = 0;
+ void __user *uaddr = (void __user *)mop->buf;
+
+ if (mop->flags || !mop->size)
+ return -EINVAL;
+
+ if (mop->size > sida_size(vcpu->arch.sie_block))
+ return -E2BIG;
+
+ if (mop->size + mop->offset > sida_size(vcpu->arch.sie_block))
+ return -E2BIG;
+
+ switch (mop->op) {
+ case KVM_S390_MEMOP_SIDA_READ:
+ r = 0;
+ if (copy_to_user(uaddr, (void *)sida_origin(vcpu->arch.sie_block) +
+ mop->offset, mop->size))
+ r = -EFAULT;
+
+ break;
+ case KVM_S390_MEMOP_SIDA_WRITE:
+ r = 0;
+ if (copy_from_user((void *)vcpu->arch.sie_block->sidad +
+ mop->offset, uaddr, mop->size))
+ r = -EFAULT;
+ break;
+ }
+ return r;
+}
+
static int kvm_s390_handle_pv_vcpu(struct kvm_vcpu *vcpu,
struct kvm_pv_cmd *cmd)
{
@@ -4708,6 +4743,20 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
r = kvm_s390_handle_pv_vcpu(vcpu, &args);
break;
}
+ case KVM_S390_SIDA_OP: {
+ struct kvm_s390_mem_op mem_op;
+
+ if (!kvm_s390_pv_is_protected(vcpu->kvm)) {
+ r = -EINVAL;
+ break;
+ }
+
+ if (copy_from_user(&mem_op, argp, sizeof(mem_op)) == 0)
+ r = kvm_s390_guest_sida_op(vcpu, &mem_op);
+ else
+ r = -EFAULT;
+ break;
+ }
#endif
default:
r = -ENOTTY;
diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c
index 24d802072ac7..50e1dc68d972 100644
--- a/arch/s390/kvm/pv.c
+++ b/arch/s390/kvm/pv.c
@@ -93,6 +93,7 @@ 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(sida_origin(vcpu->arch.sie_block));
/* Clear cpu and vm handle */
memset(&vcpu->arch.sie_block->reserved10, 0,
sizeof(vcpu->arch.sie_block->reserved10));
@@ -124,6 +125,14 @@ 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,
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index eab741bc12c3..20969ce12096 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -466,7 +466,7 @@ struct kvm_translation {
__u8 pad[5];
};
-/* for KVM_S390_MEM_OP */
+/* for KVM_S390_MEM_OP and KVM_S390_SIDA_OP */
struct kvm_s390_mem_op {
/* in */
__u64 gaddr; /* the guest address */
@@ -475,11 +475,17 @@ struct kvm_s390_mem_op {
__u32 op; /* type of operation */
__u64 buf; /* buffer in userspace */
__u8 ar; /* the access register number */
- __u8 reserved[31]; /* should be set to 0 */
+ __u8 reserved21[3]; /* should be set to 0 */
+ __u32 offset; /* offset into the sida */
+ __u8 reserved28[24]; /* should be set to 0 */
};
+
+
/* types for kvm_s390_mem_op->op */
#define KVM_S390_MEMOP_LOGICAL_READ 0
#define KVM_S390_MEMOP_LOGICAL_WRITE 1
+#define KVM_S390_MEMOP_SIDA_READ 2
+#define KVM_S390_MEMOP_SIDA_WRITE 3
/* flags for kvm_s390_mem_op->flags */
#define KVM_S390_MEMOP_F_CHECK_ONLY (1ULL << 0)
#define KVM_S390_MEMOP_F_INJECT_EXCEPTION (1ULL << 1)
@@ -1510,6 +1516,7 @@ struct kvm_pv_cmd {
/* Available with KVM_CAP_S390_PROTECTED */
#define KVM_S390_PV_COMMAND _IOW(KVMIO, 0xc5, struct kvm_pv_cmd)
#define KVM_S390_PV_COMMAND_VCPU _IOW(KVMIO, 0xc6, struct kvm_pv_cmd)
+#define KVM_S390_SIDA_OP _IOW(KVMIO, 0xc7, struct kvm_s390_mem_op)
/* Secure Encrypted Virtualization command */
enum sev_cmd_id {
--
2.24.0
