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Fri, 3 Mar 2023 15:54:32 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id b/O0IDgYAmQhSQAAMHmgww (envelope-from ); Fri, 03 Mar 2023 15:54:32 +0000 Message-ID: <4846fdcd-3e13-548b-dc2c-a47dc163885f@suse.cz> Date: Fri, 3 Mar 2023 16:54:32 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH RFC v8 23/56] crypto: ccp: Introduce snp leaked pages list Content-Language: en-US To: Michael Roth , kvm@vger.kernel.org Cc: linux-coco@lists.linux.dev, linux-mm@kvack.org, linux-crypto@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, jroedel@suse.de, thomas.lendacky@amd.com, hpa@zytor.com, ardb@kernel.org, pbonzini@redhat.com, seanjc@google.com, vkuznets@redhat.com, jmattson@google.com, luto@kernel.org, dave.hansen@linux.intel.com, slp@redhat.com, pgonda@google.com, peterz@infradead.org, srinivas.pandruvada@linux.intel.com, rientjes@google.com, dovmurik@linux.ibm.com, tobin@ibm.com, bp@alien8.de, kirill@shutemov.name, ak@linux.intel.com, tony.luck@intel.com, marcorr@google.com, sathyanarayanan.kuppuswamy@linux.intel.com, alpergun@google.com, dgilbert@redhat.com, jarkko@kernel.org, ashish.kalra@amd.com, nikunj.dadhania@amd.com References: <20230220183847.59159-1-michael.roth@amd.com> <20230220183847.59159-24-michael.roth@amd.com> From: Vlastimil Babka In-Reply-To: <20230220183847.59159-24-michael.roth@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: 9xp171wgmi3be517ghjwzoq9bb3858ph X-Rspam-User: X-Rspamd-Queue-Id: 8D2B418000E X-Rspamd-Server: rspam06 X-HE-Tag: 1677858874-137441 X-HE-Meta: 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 FJ75F/XF kqstPdnTBpSd1dLaJVsVjikAtYqfoX+cXoNVo3UMTLcYAkeTfFq+pZ5Z2gyUBjpwu3yQ+Pwy49d0DOQvpQj4ltp0qYozrsizAnGsL/lGqygGQjYgr8qvYIP8qxNFZLhOzBDq4InjBbucyu1a960dQOZEGdxn0l8W0MT6yegP99bkjMtYWjH+Lhz80Z+HUiXyvCu+8xXsksdeNgFz+Q1iIzeu8F0IDMjbfCkc23FQd0E6yiTg= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2/20/23 19:38, Michael Roth wrote: > From: Ashish Kalra > > Pages are unsafe to be released back to the page-allocator, if they > have been transitioned to firmware/guest state and can't be reclaimed > or transitioned back to hypervisor/shared state. In this case add > them to an internal leaked pages list to ensure that they are not freed > or touched/accessed to cause fatal page faults. > > Signed-off-by: Ashish Kalra > Signed-off-by: Michael Roth > --- > drivers/crypto/ccp/sev-dev.c | 28 ++++++++++++++++++++++++++++ > include/linux/psp-sev.h | 8 ++++++++ > 2 files changed, 36 insertions(+) > > diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c > index 35f605936f1b..eca4e59b0f44 100644 > --- a/drivers/crypto/ccp/sev-dev.c > +++ b/drivers/crypto/ccp/sev-dev.c > @@ -42,6 +42,12 @@ > static DEFINE_MUTEX(sev_cmd_mutex); > static struct sev_misc_dev *misc_dev; > > +/* list of pages which are leaked and cannot be reclaimed */ > +static LIST_HEAD(snp_leaked_pages_list); > +static DEFINE_SPINLOCK(snp_leaked_pages_list_lock); > + > +static atomic_long_t snp_nr_leaked_pages = ATOMIC_LONG_INIT(0); > + > static int psp_cmd_timeout = 100; > module_param(psp_cmd_timeout, int, 0644); > MODULE_PARM_DESC(psp_cmd_timeout, " default timeout value, in seconds, for PSP commands"); > @@ -188,6 +194,28 @@ static int sev_cmd_buffer_len(int cmd) > return 0; > } > > +void snp_mark_pages_offline(unsigned long pfn, unsigned int npages) Why call it offline which has usually a memory hotplug-related meaning? What about e.g. snp_leak_bad_pages() ? > +{ > + struct page *page = pfn_to_page(pfn); > + > + WARN(1, "psc failed, pfn 0x%lx pages %d (marked offline)\n", pfn, npages); > + > + spin_lock(&snp_leaked_pages_list_lock); > + while (npages--) { > + /* > + * Reuse the page's buddy list for chaining into the leaked > + * pages list. This page should not be on a free list currently > + * and is also unsafe to be added to a free list. > + */ > + list_add_tail(&page->buddy_list, &snp_leaked_pages_list); > + sev_dump_rmpentry(pfn); > + pfn++; > + } > + spin_unlock(&snp_leaked_pages_list_lock); > + atomic_long_inc(&snp_nr_leaked_pages); > +} > +EXPORT_SYMBOL_GPL(snp_mark_pages_offline); > + > static void *sev_fw_alloc(unsigned long len) > { > struct page *page; > diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h > index 46f61e3ae33b..8edf5c548fbf 100644 > --- a/include/linux/psp-sev.h > +++ b/include/linux/psp-sev.h > @@ -923,6 +923,12 @@ int sev_do_cmd(int cmd, void *data, int *psp_ret); > > void *psp_copy_user_blob(u64 uaddr, u32 len); > > +/** > + * sev_mark_pages_offline - insert non-reclaimed firmware/guest pages > + * into a leaked pages list. > + */ > +void snp_mark_pages_offline(unsigned long pfn, unsigned int npages); > + > #else /* !CONFIG_CRYPTO_DEV_SP_PSP */ > > static inline int > @@ -951,6 +957,8 @@ sev_issue_cmd_external_user(struct file *filep, unsigned int id, void *data, int > > static inline void *psp_copy_user_blob(u64 __user uaddr, u32 len) { return ERR_PTR(-EINVAL); } > > +void snp_mark_pages_offline(unsigned long pfn, unsigned int npages) {} > + > #endif /* CONFIG_CRYPTO_DEV_SP_PSP */ > > #endif /* __PSP_SEV_H__ */