Re: [PATCH 1/1] SEV: QMP support for Inject-Launch-Secret

[tobin <tobin@linux.vnet.ibm.com>]

On 2020-07-02 11:53, Dr. David Alan Gilbert wrote:
> * Tobin Feldman-Fitzthum (tobin@linux.vnet.ibm.com) wrote:
>> From: Tobin Feldman-Fitzthum <tobin@ibm.com>
>> 
>> AMD SEV allows a guest owner to inject a secret blob
>> into the memory of a virtual machine. The secret is
>> encrypted with the SEV Transport Encryption Key and
>> integrity is guaranteed with the Transport Integrity
>> Key. Although QEMU faciliates the injection of the
>> launch secret, it cannot access the secret.
>> 
>> Signed-off-by: Tobin Feldman-Fitzthum <tobin@linux.vnet.ibm.com>
>> ---
>>  include/monitor/monitor.h |  3 ++
>>  include/sysemu/sev.h      |  2 ++
>>  monitor/misc.c            |  8 ++---
>>  qapi/misc-target.json     | 18 +++++++++++
>>  target/i386/monitor.c     |  9 ++++++
>>  target/i386/sev-stub.c    |  5 +++
>>  target/i386/sev.c         | 66 
>> +++++++++++++++++++++++++++++++++++++++
>>  target/i386/trace-events  |  1 +
>>  8 files changed, 108 insertions(+), 4 deletions(-)
>> 
>> diff --git a/include/monitor/monitor.h b/include/monitor/monitor.h
>> index 1018d754a6..bf049c5b00 100644
>> --- a/include/monitor/monitor.h
>> +++ b/include/monitor/monitor.h
>> @@ -4,6 +4,7 @@
>>  #include "block/block.h"
>>  #include "qapi/qapi-types-misc.h"
>>  #include "qemu/readline.h"
>> +#include "include/exec/hwaddr.h"
>> 
>>  extern __thread Monitor *cur_mon;
>>  typedef struct MonitorHMP MonitorHMP;
>> @@ -36,6 +37,8 @@ void monitor_flush(Monitor *mon);
>>  int monitor_set_cpu(int cpu_index);
>>  int monitor_get_cpu_index(void);
>> 
>> +void *gpa2hva(MemoryRegion **p_mr, hwaddr addr, uint64_t size, Error 
>> **errp);
>> +
>>  void monitor_read_command(MonitorHMP *mon, int show_prompt);
>>  int monitor_read_password(MonitorHMP *mon, ReadLineFunc 
>> *readline_func,
>>                            void *opaque);
>> diff --git a/include/sysemu/sev.h b/include/sysemu/sev.h
>> index 98c1ec8d38..b279b293e8 100644
>> --- a/include/sysemu/sev.h
>> +++ b/include/sysemu/sev.h
>> @@ -18,4 +18,6 @@
>> 
>>  void *sev_guest_init(const char *id);
>>  int sev_encrypt_data(void *handle, uint8_t *ptr, uint64_t len);
>> +int sev_inject_launch_secret(const char *hdr, const char *secret,
>> +                             uint64_t gpa);
>>  #endif
>> diff --git a/monitor/misc.c b/monitor/misc.c
>> index 89bb970b00..b9ec8ba410 100644
>> --- a/monitor/misc.c
>> +++ b/monitor/misc.c
>> @@ -674,10 +674,10 @@ static void hmp_physical_memory_dump(Monitor 
>> *mon, const QDict *qdict)
>>      memory_dump(mon, count, format, size, addr, 1);
>>  }
>> 
>> -static void *gpa2hva(MemoryRegion **p_mr, hwaddr addr, Error **errp)
>> +void *gpa2hva(MemoryRegion **p_mr, hwaddr addr, uint64_t size, Error 
>> **errp)
>>  {
>>      MemoryRegionSection mrs = memory_region_find(get_system_memory(),
>> -                                                 addr, 1);
>> +                                                 addr, size);
>> 
>>      if (!mrs.mr) {
>>          error_setg(errp, "No memory is mapped at address 0x%" 
>> HWADDR_PRIx, addr);
>> @@ -701,7 +701,7 @@ static void hmp_gpa2hva(Monitor *mon, const QDict 
>> *qdict)
>>      MemoryRegion *mr = NULL;
>>      void *ptr;
>> 
>> -    ptr = gpa2hva(&mr, addr, &local_err);
>> +    ptr = gpa2hva(&mr, addr, 1, &local_err);
>>      if (local_err) {
>>          error_report_err(local_err);
>>          return;
>> @@ -777,7 +777,7 @@ static void hmp_gpa2hpa(Monitor *mon, const QDict 
>> *qdict)
>>      void *ptr;
>>      uint64_t physaddr;
>> 
>> -    ptr = gpa2hva(&mr, addr, &local_err);
>> +    ptr = gpa2hva(&mr, addr, 1, &local_err);
>>      if (local_err) {
>>          error_report_err(local_err);
>>          return;
>> diff --git a/qapi/misc-target.json b/qapi/misc-target.json
>> index dee3b45930..d145f916b3 100644
>> --- a/qapi/misc-target.json
>> +++ b/qapi/misc-target.json
>> @@ -200,6 +200,24 @@
>>  { 'command': 'query-sev-capabilities', 'returns': 'SevCapability',
>>    'if': 'defined(TARGET_I386)' }
>> 
>> +##
>> +# @sev-inject-launch-secret:
>> +#
>> +# This command injects a secret blob into memory of SEV guest.
>> +#
>> +# @packet-header: the launch secret packet header encoded in base64
>> +#
>> +# @secret: the launch secret data to be injected encoded in base64
>> +#
>> +# @gpa: the guest physical address where secret will be injected.
>> +#
>> +# Since: 5.1
>> +#
>> +##
>> +{ 'command': 'sev-inject-launch-secret',
>> +  'data': { 'packet-header': 'str', 'secret': 'str', 'gpa': 'uint64' 
>> },
>> +  'if': 'defined(TARGET_I386)' }
>> +
>>  ##
>>  # @dump-skeys:
>>  #
>> diff --git a/target/i386/monitor.c b/target/i386/monitor.c
>> index 27ebfa3ad2..42bcfe6dc0 100644
>> --- a/target/i386/monitor.c
>> +++ b/target/i386/monitor.c
>> @@ -736,3 +736,12 @@ SevCapability *qmp_query_sev_capabilities(Error 
>> **errp)
>> 
>>      return data;
>>  }
>> +
>> +void qmp_sev_inject_launch_secret(const char *packet_hdr,
>> +                                  const char *secret, uint64_t gpa,
>> +                                  Error **errp)
>> +{
>> +    if (sev_inject_launch_secret(packet_hdr, secret, gpa) != 0) {
>> +        error_setg(errp, "SEV inject secret failed");
>> +    }
>> +}
>> diff --git a/target/i386/sev-stub.c b/target/i386/sev-stub.c
>> index e5ee13309c..fed4588185 100644
>> --- a/target/i386/sev-stub.c
>> +++ b/target/i386/sev-stub.c
>> @@ -48,3 +48,8 @@ SevCapability *sev_get_capabilities(void)
>>  {
>>      return NULL;
>>  }
>> +int sev_inject_launch_secret(const char *hdr, const char *secret,
>> +                             uint64_t gpa)
>> +{
>> +    return 1;
>> +}
>> diff --git a/target/i386/sev.c b/target/i386/sev.c
>> index d273174ad3..b35f1ddc0c 100644
>> --- a/target/i386/sev.c
>> +++ b/target/i386/sev.c
>> @@ -28,6 +28,8 @@
>>  #include "sysemu/runstate.h"
>>  #include "trace.h"
>>  #include "migration/blocker.h"
>> +#include "exec/address-spaces.h"
>> +#include "monitor/monitor.h"
>> 
>>  #define TYPE_SEV_GUEST "sev-guest"
>>  #define SEV_GUEST(obj)                                          \
>> @@ -769,6 +771,70 @@ sev_encrypt_data(void *handle, uint8_t *ptr, 
>> uint64_t len)
>>      return 0;
>>  }
>> 
>> +int sev_inject_launch_secret(const char *packet_hdr,
>> +                             const char *secret, uint64_t gpa)
>> +{
>> +    struct kvm_sev_launch_secret input;
>> +    guchar *data = NULL, *hdr = NULL;
>> +    int error, ret = 1;
>> +    void *hva;
>> +    gsize hdr_sz = 0, data_sz = 0;
>> +    Error *local_err = NULL;
>> +    MemoryRegion *mr = NULL;
>> +
>> +    /* secret can be inject only in this state */
>> +    if (!sev_check_state(SEV_STATE_LAUNCH_SECRET)) {
> 
> This gives a build error for me; sev_check_state is declared as :
> 
> static bool
> sev_check_state(const SevGuestState *sev, SevState state)
> 
> so it's expecting the state.
> 

Ah, my bad. I think I missed the change from sev_state to sev_guest.
I will send a v2 through with all the other fixes in the near future,
unless there is anything else.

Thanks,
Tobin

>> +        error_report("SEV: Not in correct state. (LSECRET) %x",
>> +                     sev_state->state);
> 
> also it's showing as sev_state undeclared.
> 
>> +        return 1;
>> +    }
>> +
>> +    hdr = g_base64_decode(packet_hdr, &hdr_sz);
>> +    if (!hdr || hdr_sz != 52) {
> 
> Here and ...
> 
>> +        error_report("SEV: Failed to decode sequence header");
>> +        return 1;
>> +    }
>> +
>> +    data = g_base64_decode(secret, &data_sz);
>> +    if (!data || data_sz <= 0 || data_sz > 0x3E80) {
> 
> here - please don't embed magic constants; they should be a #define
> or const somewhere so we can tell what they are.
> 
>> +        error_report("SEV: Failed to decode data");
>> +        goto err;
>> +    }
>> +
>> +    hva = gpa2hva(&mr, gpa, data_sz, &local_err);
>> +    if (!hva) {
>> +        error_report("SEV: Failed to calculate guest address.");
>> +        goto err;
>> +    }
>> +
>> +    input.hdr_uaddr = (unsigned long)hdr;
>> +    input.hdr_len = hdr_sz;
>> +
>> +    input.trans_uaddr = (unsigned long)data;
>> +    input.trans_len = data_sz;
>> +
>> +    input.guest_uaddr = (unsigned long)hva;
>> +    input.guest_len = data_sz;
> 
> I'd probably use casts to uint64_t here for hdr, data, and hva
> since that's what the structure you are assigning to has.
> 
>> +
>> +    trace_kvm_sev_launch_secret(gpa, input.guest_uaddr,
>> +                                input.trans_uaddr, input.trans_len);
>> +
>> +    ret = sev_ioctl(sev_state->sev_fd, KVM_SEV_LAUNCH_SECRET,
>> +                    &input, &error);
>> +    if (ret) {
>> +        error_report("SEV: failed to inject secret ret=%d fw_error=%d 
>> '%s'",
>> +                     ret, error, fw_error_to_str(error));
>> +        goto err;
>> +    }
>> +
>> +    ret = 0;
>> +
>> +err:
>> +    g_free(data);
>> +    g_free(hdr);
>> +    return ret;
>> +}
>> +
>>  static void
>>  sev_register_types(void)
>>  {
>> diff --git a/target/i386/trace-events b/target/i386/trace-events
>> index 789c700d4a..9f299e94a2 100644
>> --- a/target/i386/trace-events
>> +++ b/target/i386/trace-events
>> @@ -15,3 +15,4 @@ kvm_sev_launch_start(int policy, void *session, void 
>> *pdh) "policy 0x%x session
>>  kvm_sev_launch_update_data(void *addr, uint64_t len) "addr %p len 
>> 0x%" PRIu64
>>  kvm_sev_launch_measurement(const char *value) "data %s"
>>  kvm_sev_launch_finish(void) ""
>> +kvm_sev_launch_secret(uint64_t hpa, uint64_t hva, uint64_t secret, 
>> int len) "hpa 0x%" PRIx64 " hva 0x%" PRIx64 " data 0x%" PRIx64 " len 
>> %d"
>> --
>> 2.20.1 (Apple Git-117)
>> 
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK