Re: [for-6.0 v5 06/13] securable guest memory: Decouple kvm_memcrypt_*() helpers from KVM

2021-01-11 Thread David Gibson
On Mon, Jan 11, 2021 at 07:13:27PM +0100, Philippe Mathieu-Daudé wrote:
> On 12/4/20 6:44 AM, David Gibson wrote:
> > The kvm_memcrypt_enabled() and kvm_memcrypt_encrypt_data() helper functions
> > don't conceptually have any connection to KVM (although it's not possible
> > in practice to use them without it).
> > 
> > They also rely on looking at the global KVMState.  But the same information
> > is available from the machine, and the only existing callers have natural
> > access to the machine state.
> > 
> > Therefore, move and rename them to helpers in securable-guest-memory.h,
> > taking an explicit machine parameter.
> > 
> > Signed-off-by: David Gibson 
> > Reviewed-by: Richard Henderson 
> > ---
> >  accel/kvm/kvm-all.c   | 27 
> >  accel/stubs/kvm-stub.c| 10 
> >  hw/i386/pc_sysfw.c|  6 +++--
> >  include/exec/securable-guest-memory.h | 36 +++
> >  include/sysemu/kvm.h  | 17 -
> >  5 files changed, 40 insertions(+), 56 deletions(-)
> ...
> 
> > +static inline int securable_guest_memory_encrypt(MachineState *machine,
> > +  uint8_t *ptr, uint64_t len)
> > +{
> > +SecurableGuestMemory *sgm = machine->sgm;
> > +
> > +if (sgm) {
> > +SecurableGuestMemoryClass *sgmc = 
> > SECURABLE_GUEST_MEMORY_GET_CLASS(sgm);
> > +
> > +if (sgmc->encrypt_data) {
> 
> Can this ever happen? Maybe use assert(sgmc->encrypt_data) instead?

It's made moot by changes in the next spin.

> 
> Otherwise:
> Reviewed-by: Philippe Mathieu-Daudé 
> 
> > +return sgmc->encrypt_data(sgm, ptr, len);
> > +}
> > +}
> > +
> > +return 1;
> > +}
> 

-- 
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


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Re: [for-6.0 v5 06/13] securable guest memory: Decouple kvm_memcrypt_*() helpers from KVM

2021-01-11 Thread Philippe Mathieu-Daudé
On 12/4/20 6:44 AM, David Gibson wrote:
> The kvm_memcrypt_enabled() and kvm_memcrypt_encrypt_data() helper functions
> don't conceptually have any connection to KVM (although it's not possible
> in practice to use them without it).
> 
> They also rely on looking at the global KVMState.  But the same information
> is available from the machine, and the only existing callers have natural
> access to the machine state.
> 
> Therefore, move and rename them to helpers in securable-guest-memory.h,
> taking an explicit machine parameter.
> 
> Signed-off-by: David Gibson 
> Reviewed-by: Richard Henderson 
> ---
>  accel/kvm/kvm-all.c   | 27 
>  accel/stubs/kvm-stub.c| 10 
>  hw/i386/pc_sysfw.c|  6 +++--
>  include/exec/securable-guest-memory.h | 36 +++
>  include/sysemu/kvm.h  | 17 -
>  5 files changed, 40 insertions(+), 56 deletions(-)
...

> +static inline int securable_guest_memory_encrypt(MachineState *machine,
> +  uint8_t *ptr, uint64_t len)
> +{
> +SecurableGuestMemory *sgm = machine->sgm;
> +
> +if (sgm) {
> +SecurableGuestMemoryClass *sgmc = 
> SECURABLE_GUEST_MEMORY_GET_CLASS(sgm);
> +
> +if (sgmc->encrypt_data) {

Can this ever happen? Maybe use assert(sgmc->encrypt_data) instead?

Otherwise:
Reviewed-by: Philippe Mathieu-Daudé 

> +return sgmc->encrypt_data(sgm, ptr, len);
> +}
> +}
> +
> +return 1;
> +}




[for-6.0 v5 06/13] securable guest memory: Decouple kvm_memcrypt_*() helpers from KVM

2020-12-03 Thread David Gibson
The kvm_memcrypt_enabled() and kvm_memcrypt_encrypt_data() helper functions
don't conceptually have any connection to KVM (although it's not possible
in practice to use them without it).

They also rely on looking at the global KVMState.  But the same information
is available from the machine, and the only existing callers have natural
access to the machine state.

Therefore, move and rename them to helpers in securable-guest-memory.h,
taking an explicit machine parameter.

Signed-off-by: David Gibson 
Reviewed-by: Richard Henderson 
---
 accel/kvm/kvm-all.c   | 27 
 accel/stubs/kvm-stub.c| 10 
 hw/i386/pc_sysfw.c|  6 +++--
 include/exec/securable-guest-memory.h | 36 +++
 include/sysemu/kvm.h  | 17 -
 5 files changed, 40 insertions(+), 56 deletions(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 92a49b328a..c6bd7b9d02 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -121,9 +121,6 @@ struct KVMState
 KVMMemoryListener memory_listener;
 QLIST_HEAD(, KVMParkedVcpu) kvm_parked_vcpus;
 
-/* securable guest memory (e.g. by guest memory encryption) */
-SecurableGuestMemory *sgm;
-
 /* For "info mtree -f" to tell if an MR is registered in KVM */
 int nr_as;
 struct KVMAs {
@@ -222,28 +219,6 @@ int kvm_get_max_memslots(void)
 return s->nr_slots;
 }
 
-bool kvm_memcrypt_enabled(void)
-{
-if (kvm_state && kvm_state->sgm) {
-return true;
-}
-
-return false;
-}
-
-int kvm_memcrypt_encrypt_data(uint8_t *ptr, uint64_t len)
-{
-SecurableGuestMemory *sgm = kvm_state->sgm;
-
-if (sgm) {
-SecurableGuestMemoryClass *sgmc = 
SECURABLE_GUEST_MEMORY_GET_CLASS(sgm);
-
-return sgmc->encrypt_data(sgm, ptr, len);
-}
-
-return 1;
-}
-
 /* Called with KVMMemoryListener.slots_lock held */
 static KVMSlot *kvm_get_free_slot(KVMMemoryListener *kml)
 {
@@ -2213,8 +2188,6 @@ static int kvm_init(MachineState *ms)
 if (ret < 0) {
 goto err;
 }
-
-kvm_state->sgm = ms->sgm;
 }
 
 ret = kvm_arch_init(ms, s);
diff --git a/accel/stubs/kvm-stub.c b/accel/stubs/kvm-stub.c
index 680e099463..0f17acfac0 100644
--- a/accel/stubs/kvm-stub.c
+++ b/accel/stubs/kvm-stub.c
@@ -81,16 +81,6 @@ int kvm_on_sigbus(int code, void *addr)
 return 1;
 }
 
-bool kvm_memcrypt_enabled(void)
-{
-return false;
-}
-
-int kvm_memcrypt_encrypt_data(uint8_t *ptr, uint64_t len)
-{
-  return 1;
-}
-
 #ifndef CONFIG_USER_ONLY
 int kvm_irqchip_add_msi_route(KVMState *s, int vector, PCIDevice *dev)
 {
diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
index b6c0822fe3..439ac78970 100644
--- a/hw/i386/pc_sysfw.c
+++ b/hw/i386/pc_sysfw.c
@@ -38,6 +38,7 @@
 #include "sysemu/sysemu.h"
 #include "hw/block/flash.h"
 #include "sysemu/kvm.h"
+#include "exec/securable-guest-memory.h"
 
 /*
  * We don't have a theoretically justifiable exact lower bound on the base
@@ -201,10 +202,11 @@ static void pc_system_flash_map(PCMachineState *pcms,
 pc_isa_bios_init(rom_memory, flash_mem, size);
 
 /* Encrypt the pflash boot ROM */
-if (kvm_memcrypt_enabled()) {
+if (securable_guest_memory_enabled(MACHINE(pcms))) {
 flash_ptr = memory_region_get_ram_ptr(flash_mem);
 flash_size = memory_region_size(flash_mem);
-ret = kvm_memcrypt_encrypt_data(flash_ptr, flash_size);
+ret = securable_guest_memory_encrypt(MACHINE(pcms),
+ flash_ptr, flash_size);
 if (ret) {
 error_report("failed to encrypt pflash rom");
 exit(1);
diff --git a/include/exec/securable-guest-memory.h 
b/include/exec/securable-guest-memory.h
index 4e2ae27040..7325b504ba 100644
--- a/include/exec/securable-guest-memory.h
+++ b/include/exec/securable-guest-memory.h
@@ -21,6 +21,7 @@
 #ifndef CONFIG_USER_ONLY
 
 #include "qom/object.h"
+#include "hw/boards.h"
 
 #define TYPE_SECURABLE_GUEST_MEMORY "securable-guest-memory"
 #define SECURABLE_GUEST_MEMORY(obj)\
@@ -43,6 +44,41 @@ typedef struct SecurableGuestMemoryClass {
 int (*encrypt_data)(SecurableGuestMemory *, uint8_t *, uint64_t);
 } SecurableGuestMemoryClass;
 
+/**
+ * securable_guest_memory_enabled - return whether guest memory is protected
+ *   from hypervisor access (with memory
+ *   encryption or otherwise)
+ * Returns: true guest memory is not directly accessible to qemu
+ *  false guest memory is directly accessible to qemu
+ */
+static inline bool securable_guest_memory_enabled(MachineState *machine)
+{
+return !!machine->sgm;
+}
+
+/**
+ * securable_guest_memory_encrypt: encrypt the memory range to make
+ *  it guest accessible
+ *