Re: [RFC v2 11/18] guest memory protection: Handle memory encrption via interface

[David Gibson <david@gibson.dropbear.id.au>]

[-- Attachment #1: Type: text/plain, Size: 10918 bytes --]

On Mon, May 25, 2020 at 12:26:55PM +0200, Greg Kurz wrote:
> 
> s/encrption/encryption

Fixed.

> On Thu, 21 May 2020 13:42:57 +1000
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > At the moment AMD SEV sets a special function pointer, plus an opaque
> > handle in KVMState to let things know how to encrypt guest memory.
> > 
> > Now that we have a QOM interface for handling things related to guest
> > memory protection, use a QOM method on that interface, rather than a bare
> > function pointer for this.
> > 
> > Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> > ---
> >  accel/kvm/kvm-all.c                    | 23 +++----
> >  accel/kvm/sev-stub.c                   |  5 --
> >  include/exec/guest-memory-protection.h |  2 +
> >  include/sysemu/sev.h                   |  6 +-
> >  target/i386/sev.c                      | 84 ++++++++++++++------------
> >  5 files changed, 63 insertions(+), 57 deletions(-)
> > 
> > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> > index d06cc04079..40997de38c 100644
> > --- a/accel/kvm/kvm-all.c
> > +++ b/accel/kvm/kvm-all.c
> > @@ -45,6 +45,7 @@
> >  #include "qapi/qapi-types-common.h"
> >  #include "qapi/qapi-visit-common.h"
> >  #include "sysemu/reset.h"
> > +#include "exec/guest-memory-protection.h"
> >  
> >  #include "hw/boards.h"
> >  
> > @@ -119,8 +120,7 @@ struct KVMState
> >      QLIST_HEAD(, KVMParkedVcpu) kvm_parked_vcpus;
> >  
> >      /* memory encryption */
> > -    void *memcrypt_handle;
> > -    int (*memcrypt_encrypt_data)(void *handle, uint8_t *ptr, uint64_t len);
> > +    GuestMemoryProtection *guest_memory_protection;
> >  
> >      /* For "info mtree -f" to tell if an MR is registered in KVM */
> >      int nr_as;
> > @@ -172,7 +172,7 @@ int kvm_get_max_memslots(void)
> >  
> >  bool kvm_memcrypt_enabled(void)
> >  {
> > -    if (kvm_state && kvm_state->memcrypt_handle) {
> > +    if (kvm_state && kvm_state->guest_memory_protection) {
> >          return true;
> >      }
> >  
> > @@ -181,10 +181,13 @@ bool kvm_memcrypt_enabled(void)
> >  
> >  int kvm_memcrypt_encrypt_data(uint8_t *ptr, uint64_t len)
> >  {
> > -    if (kvm_state->memcrypt_handle &&
> > -        kvm_state->memcrypt_encrypt_data) {
> > -        return kvm_state->memcrypt_encrypt_data(kvm_state->memcrypt_handle,
> > -                                              ptr, len);
> > +    GuestMemoryProtection *gmpo = kvm_state->guest_memory_protection;
> > +
> > +    if (gmpo) {
> > +        GuestMemoryProtectionClass *gmpc =
> > +            GUEST_MEMORY_PROTECTION_GET_CLASS(gmpo);
> > +
> > +        return gmpc->encrypt_data(gmpo, ptr, len);
> >      }
> >  
> >      return 1;
> > @@ -2101,13 +2104,11 @@ static int kvm_init(MachineState *ms)
> >       * encryption context.
> >       */
> >      if (ms->memory_encryption) {
> > -        kvm_state->memcrypt_handle = sev_guest_init(ms->memory_encryption);
> > -        if (!kvm_state->memcrypt_handle) {
> > +        kvm_state->guest_memory_protection = sev_guest_init(ms->memory_encryption);
> > +        if (!kvm_state->guest_memory_protection) {
> >              ret = -1;
> >              goto err;
> >          }
> > -
> > -        kvm_state->memcrypt_encrypt_data = sev_encrypt_data;
> >      }
> >  
> >      ret = kvm_arch_init(ms, s);
> > diff --git a/accel/kvm/sev-stub.c b/accel/kvm/sev-stub.c
> > index 4f97452585..4a5cc5569e 100644
> > --- a/accel/kvm/sev-stub.c
> > +++ b/accel/kvm/sev-stub.c
> > @@ -15,11 +15,6 @@
> >  #include "qemu-common.h"
> >  #include "sysemu/sev.h"
> >  
> > -int sev_encrypt_data(void *handle, uint8_t *ptr, uint64_t len)
> > -{
> > -    abort();
> > -}
> > -
> >  void *sev_guest_init(const char *id)
> >  {
> >      return NULL;
> 
> This requires some extra care:
> 
> accel/kvm/sev-stub.c:18:7: error: conflicting types for ‘sev_guest_init’
>  void *sev_guest_init(const char *id)
>        ^~~~~~~~~~~~~~
> In file included from accel/kvm/sev-stub.c:16:0:
> include/sysemu/sev.h:21:24: note: previous declaration of ‘sev_guest_init’ was here
>  GuestMemoryProtection *sev_guest_init(const char *id);
>                         ^~~~~~~~~~~~~~
> rules.mak:69: recipe for target 'accel/kvm/sev-stub.o' failed

Oops, that's embarrassing - I forgot to do a build on ppc.

Fixed now.

> > diff --git a/include/exec/guest-memory-protection.h b/include/exec/guest-memory-protection.h
> > index 38e9b01667..eb712a5804 100644
> > --- a/include/exec/guest-memory-protection.h
> > +++ b/include/exec/guest-memory-protection.h
> > @@ -30,6 +30,8 @@ typedef struct GuestMemoryProtection GuestMemoryProtection;
> >  
> >  typedef struct GuestMemoryProtectionClass {
> >      InterfaceClass parent;
> > +
> > +    int (*encrypt_data)(GuestMemoryProtection *, uint8_t *, uint64_t);
> >  } GuestMemoryProtectionClass;
> >  
> >  #endif /* QEMU_GUEST_MEMORY_PROTECTION_H */
> > diff --git a/include/sysemu/sev.h b/include/sysemu/sev.h
> > index 98c1ec8d38..7735a7942e 100644
> > --- a/include/sysemu/sev.h
> > +++ b/include/sysemu/sev.h
> > @@ -16,6 +16,8 @@
> >  
> >  #include "sysemu/kvm.h"
> >  
> > -void *sev_guest_init(const char *id);
> > -int sev_encrypt_data(void *handle, uint8_t *ptr, uint64_t len);
> > +typedef struct GuestMemoryProtection GuestMemoryProtection;
> > +
> > +GuestMemoryProtection *sev_guest_init(const char *id);
> > +
> >  #endif
> > diff --git a/target/i386/sev.c b/target/i386/sev.c
> > index d273174ad3..986c2fee51 100644
> > --- a/target/i386/sev.c
> > +++ b/target/i386/sev.c
> > @@ -28,6 +28,7 @@
> >  #include "sysemu/runstate.h"
> >  #include "trace.h"
> >  #include "migration/blocker.h"
> > +#include "exec/guest-memory-protection.h"
> >  
> >  #define TYPE_SEV_GUEST "sev-guest"
> >  #define SEV_GUEST(obj)                                          \
> > @@ -281,26 +282,6 @@ sev_guest_set_sev_device(Object *obj, const char *value, Error **errp)
> >      sev->sev_device = g_strdup(value);
> >  }
> >  
> > -static void
> > -sev_guest_class_init(ObjectClass *oc, void *data)
> > -{
> > -    object_class_property_add_str(oc, "sev-device",
> > -                                  sev_guest_get_sev_device,
> > -                                  sev_guest_set_sev_device);
> > -    object_class_property_set_description(oc, "sev-device",
> > -            "SEV device to use");
> > -    object_class_property_add_str(oc, "dh-cert-file",
> > -                                  sev_guest_get_dh_cert_file,
> > -                                  sev_guest_set_dh_cert_file);
> > -    object_class_property_set_description(oc, "dh-cert-file",
> > -            "guest owners DH certificate (encoded with base64)");
> > -    object_class_property_add_str(oc, "session-file",
> > -                                  sev_guest_get_session_file,
> > -                                  sev_guest_set_session_file);
> > -    object_class_property_set_description(oc, "session-file",
> > -            "guest owners session parameters (encoded with base64)");
> > -}
> > -
> >  static void
> >  sev_guest_instance_init(Object *obj)
> >  {
> > @@ -319,20 +300,6 @@ sev_guest_instance_init(Object *obj)
> >                                     OBJ_PROP_FLAG_READWRITE);
> >  }
> >  
> > -/* sev guest info */
> > -static const TypeInfo sev_guest_info = {
> > -    .parent = TYPE_OBJECT,
> > -    .name = TYPE_SEV_GUEST,
> > -    .instance_size = sizeof(SevGuestState),
> > -    .instance_finalize = sev_guest_finalize,
> > -    .class_init = sev_guest_class_init,
> > -    .instance_init = sev_guest_instance_init,
> > -    .interfaces = (InterfaceInfo[]) {
> > -        { TYPE_USER_CREATABLE },
> > -        { }
> > -    }
> > -};
> > -
> >  static SevGuestState *
> >  lookup_sev_guest_info(const char *id)
> >  {
> > @@ -670,7 +637,7 @@ sev_vm_state_change(void *opaque, int running, RunState state)
> >      }
> >  }
> >  
> > -void *
> > +GuestMemoryProtection *
> >  sev_guest_init(const char *id)
> >  {
> >      SevGuestState *sev;
> > @@ -748,16 +715,16 @@ sev_guest_init(const char *id)
> >      qemu_add_machine_init_done_notifier(&sev_machine_done_notify);
> >      qemu_add_vm_change_state_handler(sev_vm_state_change, sev);
> >  
> > -    return sev;
> > +    return GUEST_MEMORY_PROTECTION(sev);
> >  err:
> >      sev_guest = NULL;
> >      return NULL;
> >  }
> >  
> > -int
> > -sev_encrypt_data(void *handle, uint8_t *ptr, uint64_t len)
> > +static int
> > +sev_encrypt_data(GuestMemoryProtection *opaque, uint8_t *ptr, uint64_t len)
> >  {
> > -    SevGuestState *sev = handle;
> > +    SevGuestState *sev = SEV_GUEST(opaque);
> >  
> >      assert(sev);
> >  
> > @@ -769,6 +736,45 @@ sev_encrypt_data(void *handle, uint8_t *ptr, uint64_t len)
> >      return 0;
> >  }
> >  
> > +static void
> > +sev_guest_class_init(ObjectClass *oc, void *data)
> > +{
> > +    GuestMemoryProtectionClass *gmpc = GUEST_MEMORY_PROTECTION_CLASS(oc);
> > +
> > +    object_class_property_add_str(oc, "sev-device",
> > +                                  sev_guest_get_sev_device,
> > +                                  sev_guest_set_sev_device);
> > +    object_class_property_set_description(oc, "sev-device",
> > +        "SEV device to use");
> > +    object_class_property_add_str(oc, "dh-cert-file",
> > +                                  sev_guest_get_dh_cert_file,
> > +                                  sev_guest_set_dh_cert_file);
> > +    object_class_property_set_description(oc, "dh-cert-file",
> > +        "guest owners DH certificate (encoded with base64)");
> > +    object_class_property_add_str(oc, "session-file",
> > +                                  sev_guest_get_session_file,
> > +                                  sev_guest_set_session_file);
> > +    object_class_property_set_description(oc, "session-file",
> > +        "guest owners session parameters (encoded with base64)");
> > +
> > +    gmpc->encrypt_data = sev_encrypt_data;
> > +}
> > +
> > +/* sev guest info */
> > +static const TypeInfo sev_guest_info = {
> > +    .parent = TYPE_OBJECT,
> > +    .name = TYPE_SEV_GUEST,
> > +    .instance_size = sizeof(SevGuestState),
> > +    .instance_finalize = sev_guest_finalize,
> > +    .class_init = sev_guest_class_init,
> > +    .instance_init = sev_guest_instance_init,
> > +    .interfaces = (InterfaceInfo[]) {
> > +        { TYPE_GUEST_MEMORY_PROTECTION },
> > +        { TYPE_USER_CREATABLE },
> > +        { }
> > +    }
> > +};
> > +
> >  static void
> >  sev_register_types(void)
> >  {
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]