On 3/27/25 09:52, Steve Sistare wrote:
> With aux-ram-share=off, booting an SNP guest fails with:
>
> ../util/error.c:68: error_setv: Assertion `*errp == NULL' failed.
>
> This is because a CPR blocker for the guest_memfd ramblock is added
> twice, once in ram_block_add_cpr_blocker because aux-ram-share=off so
> rb->fd < 0, and once in ram_block_add for a specific guest_memfd blocker.
>
> To fix, add the guest_memfd blocker iff a generic one would not be
> added by ram_block_add_cpr_blocker.
>
> Fixes: 094a3dbc55df ("migration: ram block cpr blockers")
> Reported-by: Tom Lendacky <thomas.lenda...@amd.com>
> Reported-by: Michael Roth <michael.r...@amd.com>
> Tested-by: Tom Lendacky <thomas.lenda...@amd.com>
Re-testing shows this still fixes the SNP launch failure. So Tested-by:
tag is still good.
Thanks,
Tom
> Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
> ---
> system/physmem.c | 20 +++++++++++++-------
> 1 file changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/system/physmem.c b/system/physmem.c
> index e97de3e..333a5eb 100644
> --- a/system/physmem.c
> +++ b/system/physmem.c
> @@ -158,6 +158,7 @@ static void io_mem_init(void);
> static void memory_map_init(void);
> static void tcg_log_global_after_sync(MemoryListener *listener);
> static void tcg_commit(MemoryListener *listener);
> +static bool ram_is_cpr_compatible(RAMBlock *rb);
>
> /**
> * CPUAddressSpace: all the information a CPU needs about an AddressSpace
> @@ -1908,13 +1909,18 @@ static void ram_block_add(RAMBlock *new_block, Error
> **errp)
> goto out_free;
> }
>
> - error_setg(&new_block->cpr_blocker,
> - "Memory region %s uses guest_memfd, "
> - "which is not supported with CPR.",
> - memory_region_name(new_block->mr));
> - migrate_add_blocker_modes(&new_block->cpr_blocker, errp,
> - MIG_MODE_CPR_TRANSFER,
> - -1);
> + /*
> + * Add a specific guest_memfd blocker if a generic one would not be
> + * added by ram_block_add_cpr_blocker.
> + */
> + if (ram_is_cpr_compatible(new_block)) {
> + error_setg(&new_block->cpr_blocker,
> + "Memory region %s uses guest_memfd, "
> + "which is not supported with CPR.",
> + memory_region_name(new_block->mr));
> + migrate_add_blocker_modes(&new_block->cpr_blocker, errp,
> + MIG_MODE_CPR_TRANSFER, -1);
> + }
> }
>
> ram_size = (new_block->offset + new_block->max_length) >>
> TARGET_PAGE_BITS;
