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

[Janosch Frank <frankja@linux.ibm.com>]

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)
>