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Re: [PATCH v6 02/18] s390x: protvirt: Add diag308 subcodes 8 - 10


From: Janosch Frank
Subject: Re: [PATCH v6 02/18] s390x: protvirt: Add diag308 subcodes 8 - 10
Date: Thu, 5 Mar 2020 13:04:38 +0100
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2

On 3/4/20 6:04 PM, David Hildenbrand wrote:
> On 04.03.20 12:42, Janosch Frank wrote:
>> For diag308 subcodes 8 - 10 we have a new ipib of type 5. The ipib
>> holds the address and length of the secure execution header, as well
>> as a list of guest components.
>>
>> Each component is a block of memory, for example kernel or initrd,
>> which needs to be decrypted by the Ultravisor in order to run a
>> protected VM. The secure execution header instructs the Ultravisor on
>> how to handle the protected VM and its components.
>>
>> Subcodes 8 and 9 are similiar to 5 and 6 and subcode 10 will finally
>> start the protected guest.
>>
>> Subcodes 8-10 are not valid in protected mode, we have to do a subcode
>> 3 and then the 8 and 10 combination for a protected reboot.
>>
>> Signed-off-by: Janosch Frank <address@hidden>
>> ---
>>  hw/s390x/ipl.c      | 47 ++++++++++++++++++++++++++++++++++++++++++---
>>  hw/s390x/ipl.h      | 32 ++++++++++++++++++++++++++++++
>>  target/s390x/diag.c | 26 ++++++++++++++++++++++---
>>  3 files changed, 99 insertions(+), 6 deletions(-)
>>
>> diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
>> index 9c1ecd423c..80c6ab233a 100644
>> --- a/hw/s390x/ipl.c
>> +++ b/hw/s390x/ipl.c
>> @@ -538,15 +538,55 @@ static bool is_virtio_scsi_device(IplParameterBlock 
>> *iplb)
>>      return is_virtio_ccw_device_of_type(iplb, VIRTIO_ID_SCSI);
>>  }
>>  
>> +int s390_ipl_pv_check_components(IplParameterBlock *iplb)
> 
> What about making this
> 
> bool s390_ipl_pv_valid(IplParameterBlock *iplb)
> 
> and return true/false?

We already have iplb_valid_pv() and ipl->iplb_valid_pv.
Do you have any other more expressive name we could use?

> 
>> +{
>> +    int i;
>> +    IPLBlockPV *ipib_pv = &iplb->pv;
> 
> nit: place "int i;" down here

Ack

> 
>> +
>> +    if (ipib_pv->num_comp == 0) {
>> +        return -EINVAL;
>> +    }
>> +
>> +    for (i = 0; i < ipib_pv->num_comp; i++) {
>> +        /* Addr must be 4k aligned */
>> +        if (ipib_pv->components[i].addr & ~TARGET_PAGE_MASK) {
>> +            return -EINVAL;
>> +        }
>> +
>> +        /* Tweak prefix is monotonously increasing with each component */
> 
> should that be "monotonically increasing" ?

Ooooooh, yeah...

> 
>> +        if (i < ipib_pv->num_comp - 1 &&
>> +            ipib_pv->components[i].tweak_pref >
>> +            ipib_pv->components[i + 1].tweak_pref) {
> 
> and I assume "==" is valid then.

Nope, it should be >= in this check

> 
>> +            return -EINVAL;
>> +        }
>> +    }
>> +    return 0;
>> +}
>> +
>>  void s390_ipl_update_diag308(IplParameterBlock *iplb)
>>  {
>>      S390IPLState *ipl = get_ipl_device();
>>  
>> -    ipl->iplb = *iplb;
>> -    ipl->iplb_valid = true;
>> +    if (iplb->pbt == S390_IPL_TYPE_PV) {
>> +        ipl->iplb_pv = *iplb;
>> +        ipl->iplb_valid_pv = true;
>> +    } else {
>> +        ipl->iplb = *iplb;
>> +        ipl->iplb_valid = true;
>> +    }
>>      ipl->netboot = is_virtio_net_device(iplb);
>>  }
>>  
>> +IplParameterBlock *s390_ipl_get_iplb_secure(void)
> 
> Why suddenly the "secure" ? s390_ipl_get_iplb_pv?

Remnants of former times

> 
>> +{
>> +    S390IPLState *ipl = get_ipl_device();
>> +
>> +    if (!ipl->iplb_valid_pv) {
>> +        return NULL;
>> +    }
>> +    return &ipl->iplb_pv;
>> +}
>> +
>>  IplParameterBlock *s390_ipl_get_iplb(void)
>>  {
>>      S390IPLState *ipl = get_ipl_device();
>> @@ -561,7 +601,8 @@ void s390_ipl_reset_request(CPUState *cs, enum 
>> s390_reset reset_type)
>>  {
>>      S390IPLState *ipl = get_ipl_device();
>>  
>> -    if (reset_type == S390_RESET_EXTERNAL || reset_type == 
>> S390_RESET_REIPL) {
>> +    if (reset_type == S390_RESET_EXTERNAL || reset_type == S390_RESET_REIPL 
>> ||
>> +        reset_type == S390_RESET_PV) {
> 
> What about a switch-case now instead?
> 
>>          /* use CPU 0 for full resets */
>>          ipl->reset_cpu_index = 0;
>>      } else {
>> diff --git a/hw/s390x/ipl.h b/hw/s390x/ipl.h
>> index d4813105db..04be63cee1 100644
>> --- a/hw/s390x/ipl.h
>> +++ b/hw/s390x/ipl.h
>> @@ -15,6 +15,24 @@
>>  #include "cpu.h"
>>  #include "hw/qdev-core.h"
>>  
>> +struct IPLBlockPVComp {
>> +    uint64_t tweak_pref;
>> +    uint64_t addr;
>> +    uint64_t size;
>> +} QEMU_PACKED;
> 
> Do we need the packed here? All members are naturally aligned.

No, I'll remove them

> 
>> +typedef struct IPLBlockPVComp IPLBlockPVComp;
>> +
>> +struct IPLBlockPV {
>> +    uint8_t  reserved[87];
>> +    uint8_t  version;
>> +    uint32_t reserved70;
>> +    uint32_t num_comp;
>> +    uint64_t pv_header_addr;
>> +    uint64_t pv_header_len;
>> +    struct IPLBlockPVComp components[];
>> +} QEMU_PACKED;
> 
> Dito.
> 
> [...]
> 
>>      uint64_t compat_bios_start_addr;
>>      bool enforce_bios;
>>      bool iplb_valid;
>> +    bool iplb_valid_pv;
> 
> I'd name this "iplb_pv_valid" to match "iplb_pv".

I like matching prefixes :)

> 
>>      bool netboot;
>>      /* reset related properties don't have to be migrated or reset */
>>      enum s390_reset reset_type;
>> @@ -161,9 +185,11 @@ QEMU_BUILD_BUG_MSG(offsetof(S390IPLState, iplb) & 3, 
>> "alignment of iplb wrong");
>>  
>>  #define S390_IPL_TYPE_FCP 0x00
>>  #define S390_IPL_TYPE_CCW 0x02
>> +#define S390_IPL_TYPE_PV 0x05
>>  #define S390_IPL_TYPE_QEMU_SCSI 0xff
>>  
>>  #define S390_IPLB_HEADER_LEN 8
>> +#define S390_IPLB_MIN_PV_LEN 148
>>  #define S390_IPLB_MIN_CCW_LEN 200
>>  #define S390_IPLB_MIN_FCP_LEN 384
>>  #define S390_IPLB_MIN_QEMU_SCSI_LEN 200
>> @@ -185,4 +211,10 @@ static inline bool iplb_valid_fcp(IplParameterBlock 
>> *iplb)
>>             iplb->pbt == S390_IPL_TYPE_FCP;
>>  }
>>  
>> +static inline bool iplb_valid_pv(IplParameterBlock *iplb)
>> +{
>> +    return be32_to_cpu(iplb->len) >= S390_IPLB_MIN_PV_LEN &&
>> +           iplb->pbt == S390_IPL_TYPE_PV;
>> +}
>> +
>>  #endif
>> diff --git a/target/s390x/diag.c b/target/s390x/diag.c
>> index b5aec06d6b..945b263f0a 100644
>> --- a/target/s390x/diag.c
>> +++ b/target/s390x/diag.c
>> @@ -52,6 +52,7 @@ int handle_diag_288(CPUS390XState *env, uint64_t r1, 
>> uint64_t r3)
>>  #define DIAG_308_RC_OK              0x0001
>>  #define DIAG_308_RC_NO_CONF         0x0102
>>  #define DIAG_308_RC_INVALID         0x0402
>> +#define DIAG_308_RC_NO_PV_CONF      0x0902
>>  
>>  #define DIAG308_RESET_MOD_CLR       0
>>  #define DIAG308_RESET_LOAD_NORM     1
>> @@ -59,6 +60,9 @@ int handle_diag_288(CPUS390XState *env, uint64_t r1, 
>> uint64_t r3)
>>  #define DIAG308_LOAD_NORMAL_DUMP    4
>>  #define DIAG308_SET                 5
>>  #define DIAG308_STORE               6
>> +#define DIAG308_PV_SET              8
>> +#define DIAG308_PV_STORE            9
>> +#define DIAG308_PV_START            10
>>  
>>  static int diag308_parm_check(CPUS390XState *env, uint64_t r1, uint64_t 
>> addr,
>>                                uintptr_t ra, bool write)
>> @@ -105,6 +109,7 @@ void handle_diag_308(CPUS390XState *env, uint64_t r1, 
>> uint64_t r3, uintptr_t ra)
>>          s390_ipl_reset_request(cs, S390_RESET_REIPL);
>>          break;
>>      case DIAG308_SET:
>> +    case DIAG308_PV_SET:
>>          if (diag308_parm_check(env, r1, addr, ra, false)) {
>>              return;
>>          }
>> @@ -117,7 +122,8 @@ void handle_diag_308(CPUS390XState *env, uint64_t r1, 
>> uint64_t r3, uintptr_t ra)
>>  
>>          cpu_physical_memory_read(addr, iplb, be32_to_cpu(iplb->len));
>>  
>> -        if (!iplb_valid_ccw(iplb) && !iplb_valid_fcp(iplb)) {
>> +        if (!iplb_valid_ccw(iplb) && !iplb_valid_fcp(iplb) &&
>> +            !(iplb_valid_pv(iplb) && !s390_ipl_pv_check_components(iplb))) {
> 
> I really think we should make this s390_ipl_pv_valid(), we're mixing
> functions that return true on success with functions that return 0 on
> success. Also, can't we simply move that check into iplb_valid_pv(iplb)
> to make this here easier to read?

Yes, let me figure something out

> 
>>              env->regs[r1 + 1] = DIAG_308_RC_INVALID;
>>              goto out;
>>          }
>> @@ -128,17 +134,31 @@ out:
>>          g_free(iplb);
>>          return;
>>      case DIAG308_STORE:
>> +    case DIAG308_PV_STORE:
>>          if (diag308_parm_check(env, r1, addr, ra, true)) {
>>              return;
>>          }
>> -        iplb = s390_ipl_get_iplb();
>> +        if (subcode == DIAG308_PV_STORE) {
>> +            iplb = s390_ipl_get_iplb_secure();
>> +        } else {
>> +            iplb = s390_ipl_get_iplb();
>> +        }
>>          if (iplb) {
>>              cpu_physical_memory_write(addr, iplb, be32_to_cpu(iplb->len));
>>              env->regs[r1 + 1] = DIAG_308_RC_OK;
>>          } else {
>>              env->regs[r1 + 1] = DIAG_308_RC_NO_CONF;
>>          }
>> -        return;
>> +        break;
>> +    case DIAG308_PV_START:
>> +        iplb = s390_ipl_get_iplb_secure();
>> +        if (!iplb || !iplb_valid_pv(iplb)) {
> 
> Why do we need another iplb_valid_pv() check? I thought we would verify
> this when setting and marking valid.

Good question, I'll look into it and give this patch a dust off

> 
>> +            env->regs[r1 + 1] = DIAG_308_RC_NO_PV_CONF;
>> +            return;
>> +        }
>> +
> 
> 


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