Merge tag 'x86-urgent-2022-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull misc x86 fixes from Ingo Molnar:

 - Fix PAT on Xen, which caused i915 driver failures

 - Fix compat INT 80 entry crash on Xen PV guests

 - Fix 'MMIO Stale Data' mitigation status reporting on older Intel CPUs

 - Fix RSB stuffing regressions

 - Fix ORC unwinding on ftrace trampolines

 - Add Intel Raptor Lake CPU model number

 - Fix (work around) a SEV-SNP bootloader bug providing bogus values in
   boot_params->cc_blob_address, by ignoring the value on !SEV-SNP
   bootups.

 - Fix SEV-SNP early boot failure

 - Fix the objtool list of noreturn functions and annotate snp_abort(),
   which bug confused objtool on gcc-12.

 - Fix the documentation for retbleed

* tag 'x86-urgent-2022-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Documentation/ABI: Mention retbleed vulnerability info file for sysfs
  x86/sev: Mark snp_abort() noreturn
  x86/sev: Don't use cc_platform_has() for early SEV-SNP calls
  x86/boot: Don't propagate uninitialized boot_params->cc_blob_address
  x86/cpu: Add new Raptor Lake CPU model number
  x86/unwind/orc: Unwind ftrace trampolines with correct ORC entry
  x86/nospec: Fix i386 RSB stuffing
  x86/nospec: Unwreck the RSB stuffing
  x86/bugs: Add "unknown" reporting for MMIO Stale Data
  x86/entry: Fix entry_INT80_compat for Xen PV guests
  x86/PAT: Have pat_enabled() properly reflect state when running on Xen

1 files changed, 9 insertions, 1 deletions

diff --git a/arch/x86/mm/pat/memtype.c b/arch/x86/mm/pat/memtype.c
index d5ef64ddd35e..66a209f7eb86 100644
--- a/arch/x86/mm/pat/memtype.c
+++ b/arch/x86/mm/pat/memtype.c
@@ -62,6 +62,7 @@
 
 static bool __read_mostly pat_bp_initialized;
 static bool __read_mostly pat_disabled = !IS_ENABLED(CONFIG_X86_PAT);
+static bool __initdata pat_force_disabled = !IS_ENABLED(CONFIG_X86_PAT);
 static bool __read_mostly pat_bp_enabled;
 static bool __read_mostly pat_cm_initialized;
 
@@ -86,6 +87,7 @@ void pat_disable(const char *msg_reason)
 static int __init nopat(char *str)
 {
 	pat_disable("PAT support disabled via boot option.");
+	pat_force_disabled = true;
 	return 0;
 }
 early_param("nopat", nopat);
@@ -272,7 +274,7 @@ static void pat_ap_init(u64 pat)
 	wrmsrl(MSR_IA32_CR_PAT, pat);
 }
 
-void init_cache_modes(void)
+void __init init_cache_modes(void)
 {
 	u64 pat = 0;
 
@@ -313,6 +315,12 @@ void init_cache_modes(void)
 		 */
 		pat = PAT(0, WB) | PAT(1, WT) | PAT(2, UC_MINUS) | PAT(3, UC) |
 		      PAT(4, WB) | PAT(5, WT) | PAT(6, UC_MINUS) | PAT(7, UC);
+	} else if (!pat_force_disabled && cpu_feature_enabled(X86_FEATURE_HYPERVISOR)) {
+		/*
+		 * Clearly PAT is enabled underneath. Allow pat_enabled() to
+		 * reflect this.
+		 */
+		pat_bp_enabled = true;
 	}
 
 	__init_cache_modes(pat);