On 11/7/19 4:28 PM, Cornelia Huck wrote:
> On Thu, 24 Oct 2019 07:40:25 -0400
> Janosch Frank <frankja@xxxxxxxxxxxxx> wrote:
>
>> From: Vasily Gorbik <gor@xxxxxxxxxxxxx>
>>
>> Before being able to host protected virtual machines, donate some of
>> the memory to the ultravisor. Besides that the ultravisor might impose
>> addressing limitations for memory used to back protected VM storage. Treat
>> that limit as protected virtualization host's virtual memory limit.
>>
>> Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
>> ---
>> arch/s390/include/asm/uv.h | 16 ++++++++++++
>> arch/s390/kernel/setup.c | 3 +++
>> arch/s390/kernel/uv.c | 53 ++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 72 insertions(+)
>
> (...)
>
>> diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
>> index 35ce89695509..f7778493e829 100644
>> --- a/arch/s390/kernel/uv.c
>> +++ b/arch/s390/kernel/uv.c
>> @@ -45,4 +45,57 @@ static int __init prot_virt_setup(char *val)
>> return rc;
>> }
>> early_param("prot_virt", prot_virt_setup);
>> +
>> +static int __init uv_init(unsigned long stor_base, unsigned long stor_len)
>> +{
>> + struct uv_cb_init uvcb = {
>> + .header.cmd = UVC_CMD_INIT_UV,
>> + .header.len = sizeof(uvcb),
>> + .stor_origin = stor_base,
>> + .stor_len = stor_len,
>> + };
>> + int cc;
>> +
>> + cc = uv_call(0, (uint64_t)&uvcb);
>> + if (cc || uvcb.header.rc != UVC_RC_EXECUTED) {
>> + pr_err("Ultravisor init failed with cc: %d rc: 0x%hx\n", cc,
>> + uvcb.header.rc);
>> + return -1;
>
> Is there any reasonable case where that call might fail if we have the
> facility installed? Bad stor_base, maybe?
Yes, wrong storage locations, length, etc...
Also if we are running with more than one CPU or the Ultravisor
encountered some internal error.
>
>> + }
>> + return 0;
>> +}
>> +
>> +void __init setup_uv(void)
>> +{
>> + unsigned long uv_stor_base;
>> +
>> + if (!prot_virt_host)
>> + return;
>> +
>> + uv_stor_base = (unsigned long)memblock_alloc_try_nid(
>> + uv_info.uv_base_stor_len, SZ_1M, SZ_2G,
>> + MEMBLOCK_ALLOC_ACCESSIBLE, NUMA_NO_NODE);
>> + if (!uv_stor_base) {
>> + pr_info("Failed to reserve %lu bytes for ultravisor base storage\n",
>> + uv_info.uv_base_stor_len);
>> + goto fail;
>> + }
>> +
>> + if (uv_init(uv_stor_base, uv_info.uv_base_stor_len)) {
>> + memblock_free(uv_stor_base, uv_info.uv_base_stor_len);
>> + goto fail;
>> + }
>> +
>> + pr_info("Reserving %luMB as ultravisor base storage\n",
>> + uv_info.uv_base_stor_len >> 20);
>> + return;
>> +fail:
>> + prot_virt_host = 0;
>
> So, what happens if the user requested protected virtualization and any
> of the above failed? We turn off host support, so any attempt to start
> a protected virtualization guest on that host will fail (hopefully with
> a meaningful error), I guess.
>
STFLE 161, and the associated diag308 subcodes 8-10 will not be
available to any VM. So yes, the stuv that starts a protected guest will
print a message.
> Is there any use case where we'd want to make failure to set this up
> fatal?
Not really.
>
>> +}
>> +
>> +void adjust_to_uv_max(unsigned long *vmax)
>> +{
>> + if (prot_virt_host && *vmax > uv_info.max_sec_stor_addr)
>> + *vmax = uv_info.max_sec_stor_addr;
>> +}
>> #endif
>
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