Re: [kvm-unit-tests PATCH 1/5] lib: s390x: vm: Add kvm and lpar vm queries

Janosch Frank
2022-01-14T12:28:30Z

On 1/14/22 12:18, Claudio Imbrenda wrote:
> On Fri, 14 Jan 2022 10:02:41 +0000
> Janosch Frank <frankja@linux.ibm.com> wrote:
>
>> This patch will likely (in parts) be replaced by Pierre's patch from
>> his topology test series.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>
> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
>
> although I think there is some room for improvement, but nothing too
> serious, I'll probably fix it myself later

I think I should add this to clean up the checks in the following patches:

bool vm_is_qemu(void)
{
return vm_is_kvm() || vm_is_tcg();
}

That of course also isn't a 100% correct, we could have KVM + non-QEMU
but I'll cross that bridge when I get there.

And as I already mentioned in Pierre's patch, the STSI values are a bit
of a mystery to me since AFAIK we store KVM/Linux even if we run under TCG.

>
>> ---
>> lib/s390x/vm.c | 39 +++++++++++++++++++++++++++++++++++++++
>> lib/s390x/vm.h | 23 +++++++++++++++++++++++
>> s390x/stsi.c | 21 +--------------------
>> 3 files changed, 63 insertions(+), 20 deletions(-)
>>
>> diff --git a/lib/s390x/vm.c b/lib/s390x/vm.c
>> index a5b92863..266a81c1 100644
>> --- a/lib/s390x/vm.c
>> +++ b/lib/s390x/vm.c
>> @@ -26,6 +26,11 @@ bool vm_is_tcg(void)
>> if (initialized)
>> return is_tcg;
>>
>> + if (stsi_get_fc() < 3) {
>> + initialized = true;
>> + return false;
>> + }
>> +
>> buf = alloc_page();
>> if (!buf)
>> return false;
>> @@ -43,3 +48,37 @@ out:
>> free_page(buf);
>> return is_tcg;
>> }
>> +
>> +bool vm_is_kvm(void)
>> +{
>> + const uint8_t cpi_kvm[] = { 0xd2, 0xe5, 0xd4, 0x61 };
>> + struct stsi_322 *buf;
>> + static bool initialized = false;
>> + static bool is_kvm = false;
>> +
>> + if (initialized)
>> + return is_kvm;
>> +
>> + if (stsi_get_fc() < 3) {
>> + initialized = true;
>> + return false;
>> + }
>> +
>> + buf = alloc_page();
>> + if (!buf)
>> + return false;
>> +
>> + if (stsi(buf, 3, 2, 2))
>> + goto out;
>> +
>> + is_kvm = !(memcmp(&buf->vm[0].cpi, cpi_kvm, sizeof(cpi_kvm))) && !vm_is_tcg();
>> + initialized = true;
>> +out:
>> + free_page(buf);
>> + return is_kvm;
>> +}
>> +
>> +bool vm_is_lpar(void)
>> +{
>> + return stsi_get_fc() == 1;
>> +}
>> diff --git a/lib/s390x/vm.h b/lib/s390x/vm.h
>> index 7abba0cc..d4a82fc0 100644
>> --- a/lib/s390x/vm.h
>> +++ b/lib/s390x/vm.h
>> @@ -8,6 +8,29 @@
>> #ifndef _S390X_VM_H_
>> #define _S390X_VM_H_
>>
>> +struct stsi_322 {
>> + uint8_t reserved[31];
>> + uint8_t count;
>> + struct {
>> + uint8_t reserved2[4];
>> + uint16_t total_cpus;
>> + uint16_t conf_cpus;
>> + uint16_t standby_cpus;
>> + uint16_t reserved_cpus;
>> + uint8_t name[8];
>> + uint32_t caf;
>> + uint8_t cpi[16];
>> + uint8_t reserved5[3];
>> + uint8_t ext_name_encoding;
>> + uint32_t reserved3;
>> + uint8_t uuid[16];
>> + } vm[8];
>> + uint8_t reserved4[1504];
>> + uint8_t ext_names[8][256];
>> +};
>> +
>> bool vm_is_tcg(void);
>> +bool vm_is_kvm(void);
>> +bool vm_is_lpar(void);
>>
>> #endif /* _S390X_VM_H_ */
>> diff --git a/s390x/stsi.c b/s390x/stsi.c
>> index 391f8849..e66d07a1 100644
>> --- a/s390x/stsi.c
>> +++ b/s390x/stsi.c
>> @@ -13,27 +13,8 @@
>> #include <asm/asm-offsets.h>
>> #include <asm/interrupt.h>
>> #include <smp.h>
>> +#include <vm.h>
>>
>> -struct stsi_322 {
>> - uint8_t reserved[31];
>> - uint8_t count;
>> - struct {
>> - uint8_t reserved2[4];
>> - uint16_t total_cpus;
>> - uint16_t conf_cpus;
>> - uint16_t standby_cpus;
>> - uint16_t reserved_cpus;
>> - uint8_t name[8];
>> - uint32_t caf;
>> - uint8_t cpi[16];
>> - uint8_t reserved5[3];
>> - uint8_t ext_name_encoding;
>> - uint32_t reserved3;
>> - uint8_t uuid[16];
>> - } vm[8];
>> - uint8_t reserved4[1504];
>> - uint8_t ext_names[8][256];
>> -};
>> static uint8_t pagebuf[PAGE_SIZE * 2] __attribute__((aligned(PAGE_SIZE * 2)));
>>
>> static void test_specs(void)
>