From: Alexey Kardashevskiy Date: Tue, 17 Jun 2025 09:43:54 +0000 (+1000) Subject: crypto: ccp - Fix locking on alloc failure handling X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b4abeccb8d39db7d9b51cb0098d6458760b30a75;p=thirdparty%2Flinux.git crypto: ccp - Fix locking on alloc failure handling 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 Reviewed-by: Tom Lendacky Reviewed-by: Pratik R. Sampat Signed-off-by: Herbert Xu --- diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c index 17edc6bf56224..e058ba0277929 100644 --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -434,7 +434,7 @@ cleanup: return rc; } -static struct page *__snp_alloc_firmware_pages(gfp_t gfp_mask, int order) +static struct page *__snp_alloc_firmware_pages(gfp_t gfp_mask, int order, bool locked) { unsigned long npages = 1ul << order, paddr; struct sev_device *sev; @@ -453,7 +453,7 @@ static struct page *__snp_alloc_firmware_pages(gfp_t gfp_mask, int order) return page; paddr = __pa((unsigned long)page_address(page)); - if (rmp_mark_pages_firmware(paddr, npages, false)) + if (rmp_mark_pages_firmware(paddr, npages, locked)) return NULL; return page; @@ -463,7 +463,7 @@ void *snp_alloc_firmware_page(gfp_t gfp_mask) { struct page *page; - page = __snp_alloc_firmware_pages(gfp_mask, 0); + page = __snp_alloc_firmware_pages(gfp_mask, 0, false); return page ? page_address(page) : NULL; } @@ -498,7 +498,7 @@ static void *sev_fw_alloc(unsigned long len) { struct page *page; - page = __snp_alloc_firmware_pages(GFP_KERNEL, get_order(len)); + page = __snp_alloc_firmware_pages(GFP_KERNEL, get_order(len), true); if (!page) return NULL;