[PATCH Part1 RFC v4 28/36] x86/compressed/64: store Confidential Computing blob address in bootparams
From: Brijesh Singh <hidden>
Date: 2021-07-07 18:17:13
Also in:
kvm, linux-coco, linux-efi, linux-mm, lkml, platform-driver-x86
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Michael Roth <redacted> When the Confidential Computing blob is located by the boot/compressed kernel, store a pointer to it in bootparams->cc_blob_address to avoid the need for the run-time kernel to rescan the EFI config table to find it again. Since this function is also shared by the run-time kernel, this patch also adds the logic to make use of bootparams->cc_blob_address when it has been initialized. Signed-off-by: Michael Roth <redacted> Signed-off-by: Brijesh Singh <redacted> --- arch/x86/kernel/sev-shared.c | 38 +++++++++++++++++++++++++----------- 1 file changed, 27 insertions(+), 11 deletions(-)
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 5e0e8e208a8c..23328727caf4 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c@@ -820,7 +820,6 @@ static enum es_result vc_handle_rdtsc(struct ghcb *ghcb, return ES_OK; } -#ifdef BOOT_COMPRESSED static struct setup_data *get_cc_setup_data(struct boot_params *bp) { struct setup_data *hdr = (struct setup_data *)bp->hdr.setup_data;
@@ -840,6 +839,16 @@ static struct setup_data *get_cc_setup_data(struct boot_params *bp) * 1) Search for CC blob in the following order/precedence: * - via linux boot protocol / setup_data entry * - via EFI configuration table + * 2) If found, initialize boot_params->cc_blob_address to point to the + * blob so that uncompressed kernel can easily access it during very + * early boot without the need to re-parse EFI config table + * 3) Return a pointer to the CC blob, NULL otherwise. + * + * For run-time/uncompressed kernel: + * + * 1) Search for CC blob in the following order/precedence: + * - via linux boot protocol / setup_data entry + * - via boot_params->cc_blob_address * 2) Return a pointer to the CC blob, NULL otherwise. */ static struct cc_blob_sev_info *sev_snp_probe_cc_blob(struct boot_params *bp)
@@ -857,27 +866,34 @@ static struct cc_blob_sev_info *sev_snp_probe_cc_blob(struct boot_params *bp) goto out_verify; } +#ifdef __BOOT_COMPRESSED /* CC blob isn't in setup_data, see if it's in the EFI config table */ (void)efi_bp_find_vendor_table(bp, EFI_CC_BLOB_GUID, (unsigned long *)&cc_info); +#else + /* + * CC blob isn't in setup_data, see if boot kernel passed it via + * boot_params. + */ + if (bp->cc_blob_address) + cc_info = (struct cc_blob_sev_info *)(unsigned long)bp->cc_blob_address; +#endif out_verify: /* CC blob should be either valid or not present. Fail otherwise. */ if (cc_info && cc_info->magic != CC_BLOB_SEV_HDR_MAGIC) sev_es_terminate(1, GHCB_SNP_UNSUPPORTED); +#ifdef __BOOT_COMPRESSED + /* + * Pass run-time kernel a pointer to CC info via boot_params for easier + * access during early boot. + */ + bp->cc_blob_address = (u32)(unsigned long)cc_info; +#endif + return cc_info; } -#else -/* - * Probing for CC blob for run-time kernel will be enabled in a subsequent - * patch. For now we need to stub this out. - */ -static struct cc_blob_sev_info *sev_snp_probe_cc_blob(struct boot_params *bp) -{ - return NULL; -} -#endif /* * Initial set up of CPUID table when running identity-mapped.
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2.17.1