Merge tag 'x86_core_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull more x86 updates from Borislav Petkov:

 - Remove a bunch of asm implementing condition flags testing in KVM's
   emulator in favor of int3_emulate_jcc() which is written in C

 - Replace KVM fastops with C-based stubs which avoids problems with the
   fastop infra related to latter not adhering to the C ABI due to their
   special calling convention and, more importantly, bypassing compiler
   control-flow integrity checking because they're written in asm

 - Remove wrongly used static branches and other ugliness accumulated
   over time in hyperv's hypercall implementation with a proper static
   function call to the correct hypervisor call variant

 - Add some fixes and modifications to allow running FRED-enabled
   kernels in KVM even on non-FRED hardware

 - Add kCFI improvements like validating indirect calls and prepare for
   enabling kCFI with GCC. Add cmdline params documentation and other
   code cleanups

 - Use the single-byte 0xd6 insn as the official #UD single-byte
   undefined opcode instruction as agreed upon by both x86 vendors

 - Other smaller cleanups and touchups all over the place

* tag 'x86_core_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  x86,retpoline: Optimize patch_retpoline()
  x86,ibt: Use UDB instead of 0xEA
  x86/cfi: Remove __noinitretpoline and __noretpoline
  x86/cfi: Add "debug" option to "cfi=" bootparam
  x86/cfi: Standardize on common "CFI:" prefix for CFI reports
  x86/cfi: Document the "cfi=" bootparam options
  x86/traps: Clarify KCFI instruction layout
  compiler_types.h: Move __nocfi out of compiler-specific header
  objtool: Validate kCFI calls
  x86/fred: KVM: VMX: Always use FRED for IRQs when CONFIG_X86_FRED=y
  x86/fred: Play nice with invoking asm_fred_entry_from_kvm() on non-FRED hardware
  x86/fred: Install system vector handlers even if FRED isn't fully enabled
  x86/hyperv: Use direct call to hypercall-page
  x86/hyperv: Clean up hv_do_hypercall()
  KVM: x86: Remove fastops
  KVM: x86: Convert em_salc() to C
  KVM: x86: Introduce EM_ASM_3WCL
  KVM: x86: Introduce EM_ASM_1SRC2
  KVM: x86: Introduce EM_ASM_2CL
  KVM: x86: Introduce EM_ASM_2W
  ...

1 files changed, 13 insertions, 6 deletions

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 25773af116bc..c4febdbcfe4d 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -38,10 +38,6 @@
 bool hv_nested;
 struct ms_hyperv_info ms_hyperv;
 
-/* Used in modules via hv_do_hypercall(): see arch/x86/include/asm/mshyperv.h */
-bool hyperv_paravisor_present __ro_after_init;
-EXPORT_SYMBOL_GPL(hyperv_paravisor_present);
-
 #if IS_ENABLED(CONFIG_HYPERV)
 static inline unsigned int hv_get_nested_msr(unsigned int reg)
 {
@@ -288,8 +284,18 @@ static void __init x86_setup_ops_for_tsc_pg_clock(void)
 	old_restore_sched_clock_state = x86_platform.restore_sched_clock_state;
 	x86_platform.restore_sched_clock_state = hv_restore_sched_clock_state;
 }
+
+#ifdef CONFIG_X86_64
+DEFINE_STATIC_CALL(hv_hypercall, hv_std_hypercall);
+EXPORT_STATIC_CALL_TRAMP_GPL(hv_hypercall);
+#define hypercall_update(hc) static_call_update(hv_hypercall, hc)
+#endif
 #endif /* CONFIG_HYPERV */
 
+#ifndef hypercall_update
+#define hypercall_update(hc) (void)hc
+#endif
+
 static uint32_t  __init ms_hyperv_platform(void)
 {
 	u32 eax;
@@ -484,14 +490,14 @@ static void __init ms_hyperv_init_platform(void)
 			ms_hyperv.shared_gpa_boundary =
 				BIT_ULL(ms_hyperv.shared_gpa_boundary_bits);
 
-		hyperv_paravisor_present = !!ms_hyperv.paravisor_present;
-
 		pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",
 			ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);
 
 
 		if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) {
 			static_branch_enable(&isolation_type_snp);
+			if (!ms_hyperv.paravisor_present)
+				hypercall_update(hv_snp_hypercall);
 		} else if (hv_get_isolation_type() == HV_ISOLATION_TYPE_TDX) {
 			static_branch_enable(&isolation_type_tdx);
 
@@ -499,6 +505,7 @@ static void __init ms_hyperv_init_platform(void)
 			ms_hyperv.hints &= ~HV_X64_APIC_ACCESS_RECOMMENDED;
 
 			if (!ms_hyperv.paravisor_present) {
+				hypercall_update(hv_tdx_hypercall);
 				/*
 				 * Mark the Hyper-V TSC page feature as disabled
 				 * in a TDX VM without paravisor so that the