Re: [PATCH v4 03/16] s390x: protvirt: Support unpack facility

From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Janosch Frank <frankja@linux.ibm.com>, qemu-devel@nongnu.org
Cc: cohuck@redhat.com, qemu-s390x@nongnu.org, mihajlov@linux.ibm.com,
	david@redhat.com
Subject: Re: [PATCH v4 03/16] s390x: protvirt: Support unpack facility
Date: Mon, 24 Feb 2020 15:13:55 +0100	[thread overview]
Message-ID: <b8a56f22-c283-f344-435e-d2f36fef7ade@de.ibm.com> (raw)
In-Reply-To: <20200220125638.7241-4-frankja@linux.ibm.com>

On 20.02.20 13:56, Janosch Frank wrote:
> When a guest has saved a ipib of type 5 and calls diagnose308 with
> subcode 10, we have to setup the protected processing environment via
> Ultravisor calls. The calls are done by KVM and are exposed via an
> API.
> 
> The following steps are necessary:
> 1. Create a VM (register it with the Ultravisor)
> 2. Create secure CPUs for all of our current cpus

maybe rephrase that to reflect the enable/disable change?

> 3. Forward the secure header to the Ultravisor (has all information on
> how to decrypt the image and VM information)
> 4. Protect image pages from the host and decrypt them
> 5. Verify the image integrity
> 
> Only after step 5 a protected VM is allowed to run.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> [Changes
> to machine]

[...]

> diff --git a/hw/s390x/pv.c b/hw/s390x/pv.c
> new file mode 100644
> index 0000000000..8ae20f31c1
> --- /dev/null
> +++ b/hw/s390x/pv.c
> @@ -0,0 +1,106 @@
> +/*
> + * Secure execution functions
> + *
> + * Copyright IBM Corp. 2020
> + * Author(s):
> + *  Janosch Frank <frankja@linux.ibm.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or (at
> + * your option) any later version. See the COPYING file in the top-level
> + * directory.
> + */
> +#include "qemu/osdep.h"
> +#include <sys/ioctl.h>
> +
> +#include <linux/kvm.h>
> +
> +#include "qemu/error-report.h"
> +#include "sysemu/kvm.h"
> +#include "pv.h"
> +
> +const char *cmd_names[] = {
> +    "VM_CREATE",
> +    "VM_DESTROY",

ENABLE/DISABLE?

> +    "VM_SET_SEC_PARAMS",
> +    "VM_UNPACK",
> +    "VM_VERIFY",
> +    "VM_PREP_RESET",
> +    "VM_UNSHARE_ALL",
> +    NULL
> +};

Wild idea. Not sure if this is acceptable in QEMU.

These strings are only for the error_report, no?
Could we use a MACRO that uses this a as a string and b as the inter value?

-static int s390_pv_cmd(uint32_t cmd, void *data)
+#define S390_PV_CMD(cmd, data) s390_pv_cmd(cmd, #cmd, data)
+static int s390_pv_cmd(uint32_t cmd, const char *name, void *data)

and then replace all calls with S390_PV_CMD. (Of course also change the
error report to use name).

> +
> +static int s390_pv_cmd(uint32_t cmd, void *data)
> +{
> +    int rc;
> +    struct kvm_pv_cmd pv_cmd = {
> +        .cmd = cmd,
> +        .data = (uint64_t)data,
> +    };
> +
> +    rc = kvm_vm_ioctl(kvm_state, KVM_S390_PV_COMMAND, &pv_cmd);
> +    if (rc) {
> +        error_report("KVM PV command %d (%s) failed: header rc %x rrc %x "
> +                     "IOCTL rc: %d", cmd, cmd_names[cmd], pv_cmd.rc, pv_cmd.rrc,
> +                     rc);
> +    }
> +    return rc;
> +}
[...]

Maybe also change the subject. We do more than just unpack.