From: Brijesh Singh <brijesh.singh@xxxxxxx> The behavior and requirement for the SEV-legacy command is altered when the SNP firmware is in the INIT state. See SEV-SNP firmware specification for more details. Allocate the Trusted Memory Region (TMR) as a 2mb sized/aligned region when SNP is enabled to satisfy new requirements for the SNP. Continue allocating a 1mb region for !SNP configuration. While at it, provide API that can be used by others to allocate a page that can be used by the firmware. The immediate user for this API will be the KVM driver. The KVM driver to need to allocate a firmware context page during the guest creation. The context page need to be updated by the firmware. See the SEV-SNP specification for further details. Co-developed-by: Ashish Kalra <ashish.kalra@xxxxxxx> Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx> Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx> Signed-off-by: Michael Roth <michael.roth@xxxxxxx> --- drivers/crypto/ccp/sev-dev.c | 148 +++++++++++++++++++++++++++++++++-- include/linux/psp-sev.h | 9 +++ 2 files changed, 149 insertions(+), 8 deletions(-) diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c index eca4e59b0f44..4c12e98a1219 100644 --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -94,6 +94,13 @@ static void *sev_init_ex_buffer; */ struct sev_data_range_list *snp_range_list; +/* When SEV-SNP is enabled the TMR needs to be 2MB aligned and 2MB size. */ +#define SEV_SNP_ES_TMR_SIZE (2 * 1024 * 1024) + +static size_t sev_es_tmr_size = SEV_ES_TMR_SIZE; + +static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret); + static inline bool sev_version_greater_or_equal(u8 maj, u8 min) { struct sev_device *sev = psp_master->sev_data; @@ -216,11 +223,134 @@ void snp_mark_pages_offline(unsigned long pfn, unsigned int npages) } EXPORT_SYMBOL_GPL(snp_mark_pages_offline); +static int snp_reclaim_pages(unsigned long paddr, unsigned int npages, bool locked) +{ + /* Cbit maybe set in the paddr */ + unsigned long pfn = __sme_clr(paddr) >> PAGE_SHIFT; + int ret, err, i, n = 0; + + if (!pfn_valid(pfn)) { + pr_err("%s: Invalid PFN %lx\n", __func__, pfn); + return 0; + } + + for (i = 0; i < npages; i++, pfn++, n++) { + paddr = pfn << PAGE_SHIFT; + + if (locked) + ret = __sev_do_cmd_locked(SEV_CMD_SNP_PAGE_RECLAIM, &paddr, &err); + else + ret = sev_do_cmd(SEV_CMD_SNP_PAGE_RECLAIM, &paddr, &err); + + if (ret) + goto cleanup; + + ret = rmp_make_shared(pfn, PG_LEVEL_4K); + if (ret) + goto cleanup; + } + + return 0; + +cleanup: + /* + * If failed to reclaim the page then page is no longer safe to + * be release back to the system, leak it. + */ + snp_mark_pages_offline(pfn, npages - n); + return ret; +} + +static int rmp_mark_pages_firmware(unsigned long paddr, unsigned int npages, bool locked) +{ + /* Cbit maybe set in the paddr */ + unsigned long pfn = __sme_clr(paddr) >> PAGE_SHIFT; + int rc, n = 0, i; + + for (i = 0; i < npages; i++, n++, pfn++) { + rc = rmp_make_private(pfn, 0, PG_LEVEL_4K, 0, true); + if (rc) + goto cleanup; + } + + return 0; + +cleanup: + /* + * Try unrolling the firmware state changes by + * reclaiming the pages which were already changed to the + * firmware state. + */ + snp_reclaim_pages(paddr, n, locked); + + return rc; +} + +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; + struct page *page; + + if (!psp_master || !psp_master->sev_data) + return NULL; + + page = alloc_pages(gfp_mask, order); + if (!page) + return NULL; + + /* If SEV-SNP is initialized then add the page in RMP table. */ + sev = psp_master->sev_data; + if (!sev->snp_initialized) + return page; + + paddr = __pa((unsigned long)page_address(page)); + if (rmp_mark_pages_firmware(paddr, npages, locked)) + return NULL; + + return page; +} + +void *snp_alloc_firmware_page(gfp_t gfp_mask) +{ + struct page *page; + + page = __snp_alloc_firmware_pages(gfp_mask, 0, false); + + return page ? page_address(page) : NULL; +} +EXPORT_SYMBOL_GPL(snp_alloc_firmware_page); + +static void __snp_free_firmware_pages(struct page *page, int order, bool locked) +{ + struct sev_device *sev = psp_master->sev_data; + unsigned long paddr, npages = 1ul << order; + + if (!page) + return; + + paddr = __pa((unsigned long)page_address(page)); + if (sev->snp_initialized && + snp_reclaim_pages(paddr, npages, locked)) + return; + + __free_pages(page, order); +} + +void snp_free_firmware_page(void *addr) +{ + if (!addr) + return; + + __snp_free_firmware_pages(virt_to_page(addr), 0, false); +} +EXPORT_SYMBOL_GPL(snp_free_firmware_page); + static void *sev_fw_alloc(unsigned long len) { struct page *page; - page = alloc_pages(GFP_KERNEL, get_order(len)); + page = __snp_alloc_firmware_pages(GFP_KERNEL, get_order(len), false); if (!page) return NULL; @@ -468,7 +598,7 @@ static int __sev_init_locked(int *error) data.tmr_address = __pa(sev_es_tmr); data.flags |= SEV_INIT_FLAGS_SEV_ES; - data.tmr_len = SEV_ES_TMR_SIZE; + data.tmr_len = sev_es_tmr_size; } return __sev_do_cmd_locked(SEV_CMD_INIT, &data, error); @@ -491,7 +621,7 @@ static int __sev_init_ex_locked(int *error) data.tmr_address = __pa(sev_es_tmr); data.flags |= SEV_INIT_FLAGS_SEV_ES; - data.tmr_len = SEV_ES_TMR_SIZE; + data.tmr_len = sev_es_tmr_size; } return __sev_do_cmd_locked(SEV_CMD_INIT_EX, &data, error); @@ -982,6 +1112,8 @@ static int __sev_snp_init_locked(int *error) sev->snp_initialized = true; dev_dbg(sev->dev, "SEV-SNP firmware initialized\n"); + sev_es_tmr_size = SEV_SNP_ES_TMR_SIZE; + return rc; } @@ -1499,8 +1631,9 @@ static void sev_firmware_shutdown(struct sev_device *sev) /* The TMR area was encrypted, flush it from the cache */ wbinvd_on_all_cpus(); - free_pages((unsigned long)sev_es_tmr, - get_order(SEV_ES_TMR_SIZE)); + __snp_free_firmware_pages(virt_to_page(sev_es_tmr), + get_order(sev_es_tmr_size), + false); sev_es_tmr = NULL; } @@ -1511,8 +1644,7 @@ static void sev_firmware_shutdown(struct sev_device *sev) } if (snp_range_list) { - free_pages((unsigned long)snp_range_list, - get_order(PAGE_SIZE)); + snp_free_firmware_page(snp_range_list); snp_range_list = NULL; } @@ -1593,7 +1725,7 @@ void sev_pci_init(void) } /* Obtain the TMR memory area for SEV-ES use */ - sev_es_tmr = sev_fw_alloc(SEV_ES_TMR_SIZE); + sev_es_tmr = sev_fw_alloc(sev_es_tmr_size); if (!sev_es_tmr) dev_warn(sev->dev, "SEV: TMR allocation failed, SEV-ES support unavailable\n"); diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h index 8edf5c548fbf..d19744807471 100644 --- a/include/linux/psp-sev.h +++ b/include/linux/psp-sev.h @@ -922,6 +922,8 @@ int sev_guest_decommission(struct sev_data_decommission *data, int *error); int sev_do_cmd(int cmd, void *data, int *psp_ret); void *psp_copy_user_blob(u64 uaddr, u32 len); +void *snp_alloc_firmware_page(gfp_t mask); +void snp_free_firmware_page(void *addr); /** * sev_mark_pages_offline - insert non-reclaimed firmware/guest pages @@ -959,6 +961,13 @@ static inline void *psp_copy_user_blob(u64 __user uaddr, u32 len) { return ERR_P void snp_mark_pages_offline(unsigned long pfn, unsigned int npages) {} +static inline void *snp_alloc_firmware_page(gfp_t mask) +{ + return NULL; +} + +static inline void snp_free_firmware_page(void *addr) { } + #endif /* CONFIG_CRYPTO_DEV_SP_PSP */ #endif /* __PSP_SEV_H__ */ -- 2.25.1