Merge tag 'x86_sev_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull AMD SEV-SNP support from Borislav Petkov:
 "The third AMD confidential computing feature called Secure Nested
  Paging.

  Add to confidential guests the necessary memory integrity protection
  against malicious hypervisor-based attacks like data replay, memory
  remapping and others, thus achieving a stronger isolation from the
  hypervisor.

  At the core of the functionality is a new structure called a reverse
  map table (RMP) with which the guest has a say in which pages get
  assigned to it and gets notified when a page which it owns, gets
  accessed/modified under the covers so that the guest can take an
  appropriate action.

  In addition, add support for the whole machinery needed to launch a
  SNP guest, details of which is properly explained in each patch.

  And last but not least, the series refactors and improves parts of the
  previous SEV support so that the new code is accomodated properly and
  not just bolted on"

* tag 'x86_sev_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits)
  x86/entry: Fixup objtool/ibt validation
  x86/sev: Mark the code returning to user space as syscall gap
  x86/sev: Annotate stack change in the #VC handler
  x86/sev: Remove duplicated assignment to variable info
  x86/sev: Fix address space sparse warning
  x86/sev: Get the AP jump table address from secrets page
  x86/sev: Add missing __init annotations to SEV init routines
  virt: sevguest: Rename the sevguest dir and files to sev-guest
  virt: sevguest: Change driver name to reflect generic SEV support
  x86/boot: Put globals that are accessed early into the .data section
  x86/boot: Add an efi.h header for the decompressor
  virt: sevguest: Fix bool function returning negative value
  virt: sevguest: Fix return value check in alloc_shared_pages()
  x86/sev-es: Replace open-coded hlt-loop with sev_es_terminate()
  virt: sevguest: Add documentation for SEV-SNP CPUID Enforcement
  virt: sevguest: Add support to get extended report
  virt: sevguest: Add support to derive key
  virt: Add SEV-SNP guest driver
  x86/sev: Register SEV-SNP guest request platform device
  x86/sev: Provide support for SNP guest request NAEs
  ...

1 files changed, 16 insertions, 13 deletions

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 4f5ecbbaae77..c185f4831498 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -143,7 +143,20 @@ static unsigned long __head sme_postprocess_startup(struct boot_params *bp, pmdv
 	if (sme_get_me_mask()) {
 		vaddr = (unsigned long)__start_bss_decrypted;
 		vaddr_end = (unsigned long)__end_bss_decrypted;
+
 		for (; vaddr < vaddr_end; vaddr += PMD_SIZE) {
+			/*
+			 * On SNP, transition the page to shared in the RMP table so that
+			 * it is consistent with the page table attribute change.
+			 *
+			 * __start_bss_decrypted has a virtual address in the high range
+			 * mapping (kernel .text). PVALIDATE, by way of
+			 * early_snp_set_memory_shared(), requires a valid virtual
+			 * address but the kernel is currently running off of the identity
+			 * mapping so use __pa() to get a *currently* valid virtual address.
+			 */
+			early_snp_set_memory_shared(__pa(vaddr), __pa(vaddr), PTRS_PER_PMD);
+
 			i = pmd_index(vaddr);
 			pmd[i] -= sme_get_me_mask();
 		}
@@ -192,9 +205,6 @@ unsigned long __head __startup_64(unsigned long physaddr,
 	if (load_delta & ~PMD_PAGE_MASK)
 		for (;;);
 
-	/* Activate Secure Memory Encryption (SME) if supported and enabled */
-	sme_enable(bp);
-
 	/* Include the SME encryption mask in the fixup value */
 	load_delta += sme_get_me_mask();
 
@@ -308,15 +318,6 @@ unsigned long __head __startup_64(unsigned long physaddr,
 	return sme_postprocess_startup(bp, pmd);
 }
 
-unsigned long __startup_secondary_64(void)
-{
-	/*
-	 * Return the SME encryption mask (if SME is active) to be used as a
-	 * modifier for the initial pgdir entry programmed into CR3.
-	 */
-	return sme_get_me_mask();
-}
-
 /* Wipe all early page tables except for the kernel symbol map */
 static void __init reset_early_page_tables(void)
 {
@@ -600,8 +601,10 @@ static void startup_64_load_idt(unsigned long physbase)
 void early_setup_idt(void)
 {
 	/* VMM Communication Exception */
-	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))
+	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
+		setup_ghcb();
 		set_bringup_idt_handler(bringup_idt_table, X86_TRAP_VC, vc_boot_ghcb);
+	}
 
 	bringup_idt_descr.address = (unsigned long)bringup_idt_table;
 	native_load_idt(&bringup_idt_descr);