* Singh, Brijesh (brijesh.si...@amd.com) wrote:
> When memory encryption is enabled, the guest memory will be encrypted with
> the guest specific key. The patch introduces RAM_SAVE_FLAG_ENCRYPTED_PAGE
> flag to distinguish the encrypted data from plaintext. Encrypted pages
> may need special handling. The kvm_memcrypt_save_outgoing_page() is used
> by the sender to write the encrypted pages onto the socket, similarly the
> kvm_memcrypt_load_incoming_page() is used by the target to read the
> encrypted pages from the socket and load into the guest memory.
>
> Signed-off-by: Brijesh Singh <brijesh.si...@amd.com>
> ---
> migration/ram.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 53 insertions(+), 1 deletion(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index 908517fc2b..3c8977d508 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -57,6 +57,7 @@
> #include "qemu/uuid.h"
> #include "savevm.h"
> #include "qemu/iov.h"
> +#include "sysemu/kvm.h"
>
> /***********************************************************/
> /* ram save/restore */
> @@ -76,6 +77,7 @@
> #define RAM_SAVE_FLAG_XBZRLE 0x40
> /* 0x80 is reserved in migration.h start with 0x100 next */
> #define RAM_SAVE_FLAG_COMPRESS_PAGE 0x100
> +#define RAM_SAVE_FLAG_ENCRYPTED_PAGE 0x200
OK, that's our very last usable flag! Use it wisely!
> static inline bool is_zero_range(uint8_t *p, uint64_t size)
> {
> @@ -460,6 +462,9 @@ static QemuCond decomp_done_cond;
> static bool do_compress_ram_page(QEMUFile *f, z_stream *stream, RAMBlock
> *block,
> ram_addr_t offset, uint8_t *source_buf);
>
> +static int ram_save_encrypted_page(RAMState *rs, PageSearchStatus *pss,
> + bool last_stage);
> +
> static void *do_data_compress(void *opaque)
> {
> CompressParam *param = opaque;
> @@ -2006,6 +2011,36 @@ static int ram_save_multifd_page(RAMState *rs,
> RAMBlock *block,
> return 1;
> }
>
> +/**
> + * ram_save_encrypted_page - send the given encrypted page to the stream
> + */
> +static int ram_save_encrypted_page(RAMState *rs, PageSearchStatus *pss,
> + bool last_stage)
> +{
> + int ret;
> + uint8_t *p;
> + RAMBlock *block = pss->block;
> + ram_addr_t offset = pss->page << TARGET_PAGE_BITS;
> + uint64_t bytes_xmit;
> +
> + p = block->host + offset;
> +
> + ram_counters.transferred +=
> + save_page_header(rs, rs->f, block,
> + offset | RAM_SAVE_FLAG_ENCRYPTED_PAGE);
> +
> + ret = kvm_memcrypt_save_outgoing_page(rs->f, p,
I think you need to somehow abstract the kvm_memcrypt stuff; nothing
else in migration actually knows it's dealing with kvm. So there
should be some indirection - probably through the cpu or the machine
type or something.
Also, this isn't bisectable - you can't make this call in this patch
because you don't define/declare this function until a later patch.
> + TARGET_PAGE_SIZE, &bytes_xmit);
> + if (ret) {
> + return -1;
> + }
> +
> + ram_counters.transferred += bytes_xmit;
> + ram_counters.normal++;
> +
> + return 1;
> +}
> +
> static bool do_compress_ram_page(QEMUFile *f, z_stream *stream, RAMBlock
> *block,
> ram_addr_t offset, uint8_t *source_buf)
> {
> @@ -2450,6 +2485,16 @@ static int ram_save_target_page(RAMState *rs,
> PageSearchStatus *pss,
> return res;
> }
>
> + /*
> + * If memory encryption is enabled then use memory encryption APIs
> + * to write the outgoing buffer to the wire. The encryption APIs
> + * will take care of accessing the guest memory and re-encrypt it
> + * for the transport purposes.
> + */
> + if (kvm_memcrypt_enabled()) {
> + return ram_save_encrypted_page(rs, pss, last_stage);
> + }
> +
> if (save_compress_page(rs, block, offset)) {
> return 1;
> }
> @@ -4271,7 +4316,8 @@ static int ram_load(QEMUFile *f, void *opaque, int
> version_id)
> }
>
> if (flags & (RAM_SAVE_FLAG_ZERO | RAM_SAVE_FLAG_PAGE |
> - RAM_SAVE_FLAG_COMPRESS_PAGE | RAM_SAVE_FLAG_XBZRLE)) {
> + RAM_SAVE_FLAG_COMPRESS_PAGE | RAM_SAVE_FLAG_XBZRLE |
> + RAM_SAVE_FLAG_ENCRYPTED_PAGE)) {
> RAMBlock *block = ram_block_from_stream(f, flags);
>
> /*
> @@ -4391,6 +4437,12 @@ static int ram_load(QEMUFile *f, void *opaque, int
> version_id)
> break;
> }
> break;
> + case RAM_SAVE_FLAG_ENCRYPTED_PAGE:
> + if (kvm_memcrypt_load_incoming_page(f, host)) {
> + error_report("Failed to encrypted incoming data");
'Failed to *load* encrypted page' ?
> + ret = -EINVAL;
Do you want to actually return an error code here from
kvm_memcrypt_load_incoming_page, so we can keep hold of whether
it was something like a simple network error for the file stream
or something more complex.
Dave
> + }
> + break;
> case RAM_SAVE_FLAG_EOS:
> /* normal exit */
> multifd_recv_sync_main();
> --
> 2.17.1
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
