Re: [PATCH] crypto/ccp: Fix locking on alloc failure handling

[Herbert Xu <herbert@gondor.apana.org.au>]

On Tue, Jun 17, 2025 at 07:43:54PM +1000, Alexey Kardashevskiy wrote:
> The __snp_alloc_firmware_pages() helper allocates pages in the firmware
> state (alloc + rmpupdate). In case of failed rmpupdate, it tries
> reclaiming pages with already changed state. This requires calling
> the PSP firmware and since there is sev_cmd_mutex to guard such calls,
> the helper takes a "locked" parameter so specify if the lock needs to
> be held.
> 
> Most calls happen from snp_alloc_firmware_page() which executes without
> the lock. However
> 
> commit 24512afa4336 ("crypto: ccp: Handle the legacy TMR allocation when SNP is enabled")
> 
> switched sev_fw_alloc() from alloc_pages() (which does not call the PSP) to
> __snp_alloc_firmware_pages() (which does) but did not account for the fact
> that sev_fw_alloc() is called from __sev_platform_init_locked()
> (via __sev_platform_init_handle_tmr()) and executes with the lock held.
> 
> Add a "locked" parameter to __snp_alloc_firmware_pages().
> Make sev_fw_alloc() use the new parameter to prevent potential deadlock in
> rmp_mark_pages_firmware() if rmpupdate() failed.
> 
> Fixes: 24512afa4336 ("crypto: ccp: Handle the legacy TMR allocation when SNP is enabled")
> Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
> ---
>  drivers/crypto/ccp/sev-dev.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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