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Subject[PATCH] x86/sev: Add AMD_SEV_ES_GUEST Kconfig for including SEV-ES support
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Introduce a new Kconfig, AMD_SEV_ES_GUEST, to control the inclusion of
support for running as an SEV-ES guest. Pivoting on AMD_MEM_ENCRYPT for
guest SEV-ES support is undesirable for host-only kernel builds as
AMD_MEM_ENCRYPT is also required to enable KVM/host support for SEV and
SEV-ES.

A dedicated Kconfig also makes it easier to understand exactly what is
and isn't support in a given configuration.

Opportunistically update the AMD_MEM_ENCRYPT help text to note that it
also enables support for SEV guests.

Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---

Tested everything except an actual SEV-ES guest, I don't yet have a
workflow for testing those.

arch/x86/Kconfig | 13 ++++++++++++-
arch/x86/boot/compressed/Makefile | 2 +-
arch/x86/boot/compressed/idt_64.c | 7 ++++---
arch/x86/boot/compressed/idt_handlers_64.S | 2 +-
arch/x86/boot/compressed/misc.h | 5 ++++-
arch/x86/entry/entry_64.S | 2 +-
arch/x86/include/asm/idtentry.h | 2 +-
arch/x86/include/asm/mem_encrypt.h | 12 ++++++++----
arch/x86/include/asm/realmode.h | 4 ++--
arch/x86/include/asm/sev-es.h | 2 +-
arch/x86/kernel/Makefile | 2 +-
arch/x86/kernel/head64.c | 6 +++---
arch/x86/kernel/head_64.S | 6 +++---
arch/x86/kernel/idt.c | 2 +-
arch/x86/kernel/kvm.c | 4 ++--
arch/x86/mm/mem_encrypt.c | 2 ++
arch/x86/realmode/rm/header.S | 2 +-
arch/x86/realmode/rm/trampoline_64.S | 4 ++--
18 files changed, 50 insertions(+), 29 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 21f851179ff0..5f03e6313113 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1527,12 +1527,14 @@ config AMD_MEM_ENCRYPT
select DYNAMIC_PHYSICAL_MASK
select ARCH_USE_MEMREMAP_PROT
select ARCH_HAS_FORCE_DMA_UNENCRYPTED
- select INSTRUCTION_DECODER
help
Say yes to enable support for the encryption of system memory.
This requires an AMD processor that supports Secure Memory
Encryption (SME).

+ This also enables support for running as a Secure Encrypted
+ Virtualization (SEV) guest.
+
config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
bool "Activate AMD Secure Memory Encryption (SME) by default"
default y
@@ -1547,6 +1549,15 @@ config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
If set to N, then the encryption of system memory can be
activated with the mem_encrypt=on command line option.

+config AMD_SEV_ES_GUEST
+ bool "AMD Secure Encrypted Virtualization - Encrypted State (SEV-ES) Guest support"
+ depends on AMD_MEM_ENCRYPT
+ select INSTRUCTION_DECODER
+ help
+ Enable support for running as a Secure Encrypted Virtualization -
+ Encrypted State (SEV-ES) Guest. This enables SEV-ES boot protocol
+ changes, #VC handling, SEV-ES specific hypercalls, etc...
+
# Common NUMA Features
config NUMA
bool "NUMA Memory Allocation and Scheduler Support"
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index e0bc3988c3fa..8c036b6fc0c2 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -92,7 +92,7 @@ ifdef CONFIG_X86_64
vmlinux-objs-y += $(obj)/idt_64.o $(obj)/idt_handlers_64.o
vmlinux-objs-y += $(obj)/mem_encrypt.o
vmlinux-objs-y += $(obj)/pgtable_64.o
- vmlinux-objs-$(CONFIG_AMD_MEM_ENCRYPT) += $(obj)/sev-es.o
+ vmlinux-objs-$(CONFIG_AMD_SEV_ES_GUEST) += $(obj)/sev-es.o
endif

vmlinux-objs-$(CONFIG_ACPI) += $(obj)/acpi.o
diff --git a/arch/x86/boot/compressed/idt_64.c b/arch/x86/boot/compressed/idt_64.c
index 804a502ee0d2..916dde4a84b6 100644
--- a/arch/x86/boot/compressed/idt_64.c
+++ b/arch/x86/boot/compressed/idt_64.c
@@ -33,8 +33,9 @@ void load_stage1_idt(void)
boot_idt_desc.address = (unsigned long)boot_idt;


- if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))
- set_idt_entry(X86_TRAP_VC, boot_stage1_vc);
+#ifdef CONFIG_AMD_SEV_ES_GUEST
+ set_idt_entry(X86_TRAP_VC, boot_stage1_vc);
+#endif

load_boot_idt(&boot_idt_desc);
}
@@ -46,7 +47,7 @@ void load_stage2_idt(void)

set_idt_entry(X86_TRAP_PF, boot_page_fault);

-#ifdef CONFIG_AMD_MEM_ENCRYPT
+#ifdef CONFIG_AMD_SEV_ES_GUEST
set_idt_entry(X86_TRAP_VC, boot_stage2_vc);
#endif

diff --git a/arch/x86/boot/compressed/idt_handlers_64.S b/arch/x86/boot/compressed/idt_handlers_64.S
index 22890e199f5b..b2b1fad0d0e2 100644
--- a/arch/x86/boot/compressed/idt_handlers_64.S
+++ b/arch/x86/boot/compressed/idt_handlers_64.S
@@ -71,7 +71,7 @@ SYM_FUNC_END(\name)

EXCEPTION_HANDLER boot_page_fault do_boot_page_fault error_code=1

-#ifdef CONFIG_AMD_MEM_ENCRYPT
+#ifdef CONFIG_AMD_SEV_ES_GUEST
EXCEPTION_HANDLER boot_stage1_vc do_vc_no_ghcb error_code=1
EXCEPTION_HANDLER boot_stage2_vc do_boot_stage2_vc error_code=1
#endif
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 901ea5ebec22..3a0393d50e92 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -118,7 +118,7 @@ static inline void console_init(void)

void set_sev_encryption_mask(void);

-#ifdef CONFIG_AMD_MEM_ENCRYPT
+#ifdef CONFIG_AMD_SEV_ES_GUEST
void sev_es_shutdown_ghcb(void);
extern bool sev_es_check_ghcb_fault(unsigned long address);
#else
@@ -157,8 +157,11 @@ extern struct desc_ptr boot_idt_desc;

/* IDT Entry Points */
void boot_page_fault(void);
+
+#ifdef CONFIG_AMD_SEV_ES_GUEST
void boot_stage1_vc(void);
void boot_stage2_vc(void);
+#endif

unsigned long sev_verify_cbit(unsigned long cr3);

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index cad08703c4ad..98e52ec3cbf6 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -448,7 +448,7 @@ _ASM_NOKPROBE(\asmsym)
SYM_CODE_END(\asmsym)
.endm

-#ifdef CONFIG_AMD_MEM_ENCRYPT
+#ifdef CONFIG_AMD_SEV_ES_GUEST
/**
* idtentry_vc - Macro to generate entry stub for #VC
* @vector: Vector number
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index 247a60a47331..bc3a22d67741 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -607,7 +607,7 @@ DECLARE_IDTENTRY_RAW(X86_TRAP_DB, xenpv_exc_debug);
DECLARE_IDTENTRY_DF(X86_TRAP_DF, exc_double_fault);

/* #VC */
-#ifdef CONFIG_AMD_MEM_ENCRYPT
+#ifdef CONFIG_AMD_SEV_ES_GUEST
DECLARE_IDTENTRY_VC(X86_TRAP_VC, exc_vmm_communication);
#endif

diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 31c4df123aa0..a3f04b9b1a11 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -50,10 +50,8 @@ void __init mem_encrypt_free_decrypted_mem(void);
/* Architecture __weak replacement functions */
void __init mem_encrypt_init(void);

-void __init sev_es_init_vc_handling(void);
bool sme_active(void);
bool sev_active(void);
-bool sev_es_active(void);

#define __bss_decrypted __section(".bss..decrypted")

@@ -75,10 +73,8 @@ static inline void __init sev_setup_arch(void) { }
static inline void __init sme_encrypt_kernel(struct boot_params *bp) { }
static inline void __init sme_enable(struct boot_params *bp) { }

-static inline void sev_es_init_vc_handling(void) { }
static inline bool sme_active(void) { return false; }
static inline bool sev_active(void) { return false; }
-static inline bool sev_es_active(void) { return false; }

static inline int __init
early_set_memory_decrypted(unsigned long vaddr, unsigned long size) { return 0; }
@@ -91,6 +87,14 @@ static inline void mem_encrypt_free_decrypted_mem(void) { }

#endif /* CONFIG_AMD_MEM_ENCRYPT */

+#ifdef CONFIG_AMD_SEV_ES_GUEST
+bool sev_es_active(void);
+void __init sev_es_init_vc_handling(void);
+#else
+static inline bool sev_es_active(void) { return false; }
+static inline void sev_es_init_vc_handling(void) { }
+#endif /* CONFIG_AMD_SEV_ES_GUEST */
+
/*
* The __sme_pa() and __sme_pa_nodebug() macros are meant for use when
* writing to or comparing values from the cr3 register. Having the
diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h
index 5db5d083c873..353449b26589 100644
--- a/arch/x86/include/asm/realmode.h
+++ b/arch/x86/include/asm/realmode.h
@@ -21,7 +21,7 @@ struct real_mode_header {
/* SMP trampoline */
u32 trampoline_start;
u32 trampoline_header;
-#ifdef CONFIG_AMD_MEM_ENCRYPT
+#ifdef CONFIG_AMD_SEV_ES_GUEST
u32 sev_es_trampoline_start;
#endif
#ifdef CONFIG_X86_64
@@ -60,7 +60,7 @@ extern unsigned char real_mode_blob_end[];
extern unsigned long initial_code;
extern unsigned long initial_gs;
extern unsigned long initial_stack;
-#ifdef CONFIG_AMD_MEM_ENCRYPT
+#ifdef CONFIG_AMD_SEV_ES_GUEST
extern unsigned long initial_vc_handler;
#endif

diff --git a/arch/x86/include/asm/sev-es.h b/arch/x86/include/asm/sev-es.h
index cf1d957c7091..146dc77dc67e 100644
--- a/arch/x86/include/asm/sev-es.h
+++ b/arch/x86/include/asm/sev-es.h
@@ -81,7 +81,7 @@ extern void vc_no_ghcb(void);
extern void vc_boot_ghcb(void);
extern bool handle_vc_boot_ghcb(struct pt_regs *regs);

-#ifdef CONFIG_AMD_MEM_ENCRYPT
+#ifdef CONFIG_AMD_SEV_ES_GUEST
extern struct static_key_false sev_es_enable_key;
extern void __sev_es_ist_enter(struct pt_regs *regs);
extern void __sev_es_ist_exit(void);
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 5eeb808eb024..d2119dc1e6f9 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -150,7 +150,7 @@ obj-$(CONFIG_UNWINDER_ORC) += unwind_orc.o
obj-$(CONFIG_UNWINDER_FRAME_POINTER) += unwind_frame.o
obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o

-obj-$(CONFIG_AMD_MEM_ENCRYPT) += sev-es.o
+obj-$(CONFIG_AMD_SEV_ES_GUEST) += sev-es.o
###
# 64 bit specific files
ifeq ($(CONFIG_X86_64),y)
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 5e9beb77cafd..dafe13db714c 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -405,7 +405,7 @@ void __init do_early_exception(struct pt_regs *regs, int trapnr)
early_make_pgtable(native_read_cr2()))
return;

- if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT) &&
+ if (IS_ENABLED(CONFIG_AMD_SEV_ES_GUEST) &&
trapnr == X86_TRAP_VC && handle_vc_boot_ghcb(regs))
return;

@@ -563,7 +563,7 @@ static void startup_64_load_idt(unsigned long physbase)
gate_desc *idt = fixup_pointer(bringup_idt_table, physbase);


- if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
+ if (IS_ENABLED(CONFIG_AMD_SEV_ES_GUEST)) {
void *handler;

/* VMM Communication Exception */
@@ -579,7 +579,7 @@ 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_SEV_ES_GUEST))
set_bringup_idt_handler(bringup_idt_table, X86_TRAP_VC, vc_boot_ghcb);

bringup_idt_descr.address = (unsigned long)bringup_idt_table;
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 04bddaaba8e2..01243ec06ee6 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -300,7 +300,7 @@ SYM_CODE_START(start_cpu0)
SYM_CODE_END(start_cpu0)
#endif

-#ifdef CONFIG_AMD_MEM_ENCRYPT
+#ifdef CONFIG_AMD_SEV_ES_GUEST
/*
* VC Exception handler used during early boot when running on kernel
* addresses, but before the switch to the idt_table can be made.
@@ -338,7 +338,7 @@ SYM_CODE_END(vc_boot_ghcb)
.balign 8
SYM_DATA(initial_code, .quad x86_64_start_kernel)
SYM_DATA(initial_gs, .quad INIT_PER_CPU_VAR(fixed_percpu_data))
-#ifdef CONFIG_AMD_MEM_ENCRYPT
+#ifdef CONFIG_AMD_SEV_ES_GUEST
SYM_DATA(initial_vc_handler, .quad handle_vc_boot_ghcb)
#endif

@@ -403,7 +403,7 @@ SYM_CODE_START_LOCAL(early_idt_handler_common)
jmp restore_regs_and_return_to_kernel
SYM_CODE_END(early_idt_handler_common)

-#ifdef CONFIG_AMD_MEM_ENCRYPT
+#ifdef CONFIG_AMD_SEV_ES_GUEST
/*
* VC Exception handler used during very early boot. The
* early_idt_handler_array can't be used because it returns via the
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index ee1a283f8e96..ab783e81b806 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -232,7 +232,7 @@ static const __initconst struct idt_data ist_idts[] = {
#ifdef CONFIG_X86_MCE
ISTG(X86_TRAP_MC, asm_exc_machine_check, IST_INDEX_MCE),
#endif
-#ifdef CONFIG_AMD_MEM_ENCRYPT
+#ifdef CONFIG_AMD_SEV_ES_GUEST
ISTG(X86_TRAP_VC, asm_exc_vmm_communication, IST_INDEX_VC),
#endif
};
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 5e78e01ca3b4..69efdd20836a 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -751,7 +751,7 @@ static void __init kvm_init_platform(void)
x86_platform.apic_post_init = kvm_apic_init;
}

-#if defined(CONFIG_AMD_MEM_ENCRYPT)
+#ifdef CONFIG_AMD_SEV_ES_GUEST
static void kvm_sev_es_hcall_prepare(struct ghcb *ghcb, struct pt_regs *regs)
{
/* RAX and CPL are already in the GHCB */
@@ -776,7 +776,7 @@ const __initconst struct hypervisor_x86 x86_hyper_kvm = {
.init.x2apic_available = kvm_para_available,
.init.msi_ext_dest_id = kvm_msi_ext_dest_id,
.init.init_platform = kvm_init_platform,
-#if defined(CONFIG_AMD_MEM_ENCRYPT)
+#ifdef CONFIG_AMD_SEV_ES_GUEST
.runtime.sev_es_hcall_prepare = kvm_sev_es_hcall_prepare,
.runtime.sev_es_hcall_finish = kvm_sev_es_hcall_finish,
#endif
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index c79e5736ab2b..a527537133d1 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -383,11 +383,13 @@ bool sev_active(void)
return sev_status & MSR_AMD64_SEV_ENABLED;
}

+#ifdef CONFIG_AMD_SEV_ES_GUEST
/* Needs to be called from non-instrumentable code */
bool noinstr sev_es_active(void)
{
return sev_status & MSR_AMD64_SEV_ES_ENABLED;
}
+#endif

/* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */
bool force_dma_unencrypted(struct device *dev)
diff --git a/arch/x86/realmode/rm/header.S b/arch/x86/realmode/rm/header.S
index 8c1db5bf5d78..88b2435b52d5 100644
--- a/arch/x86/realmode/rm/header.S
+++ b/arch/x86/realmode/rm/header.S
@@ -20,7 +20,7 @@ SYM_DATA_START(real_mode_header)
/* SMP trampoline */
.long pa_trampoline_start
.long pa_trampoline_header
-#ifdef CONFIG_AMD_MEM_ENCRYPT
+#ifdef CONFIG_AMD_SEV_ES_GUEST
.long pa_sev_es_trampoline_start
#endif
#ifdef CONFIG_X86_64
diff --git a/arch/x86/realmode/rm/trampoline_64.S b/arch/x86/realmode/rm/trampoline_64.S
index 84c5d1b33d10..9830f3a3a90c 100644
--- a/arch/x86/realmode/rm/trampoline_64.S
+++ b/arch/x86/realmode/rm/trampoline_64.S
@@ -81,7 +81,7 @@ no_longmode:
jmp no_longmode
SYM_CODE_END(trampoline_start)

-#ifdef CONFIG_AMD_MEM_ENCRYPT
+#ifdef CONFIG_AMD_SEV_ES_GUEST
/* SEV-ES supports non-zero IP for entry points - no alignment needed */
SYM_CODE_START(sev_es_trampoline_start)
cli # We should be safe anyway
@@ -98,7 +98,7 @@ SYM_CODE_START(sev_es_trampoline_start)

jmp .Lswitch_to_protected
SYM_CODE_END(sev_es_trampoline_start)
-#endif /* CONFIG_AMD_MEM_ENCRYPT */
+#endif /* CONFIG_AMD_SEV_ES_GUEST */

#include "../kernel/verify_cpu.S"

--
2.30.0.284.gd98b1dd5eaa7-goog
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