Commit 885689e4 authored by Tom Lendacky's avatar Tom Lendacky Committed by Borislav Petkov
Browse files

x86/sev-es: Setup per-CPU GHCBs for the runtime handler 



The runtime handler needs one GHCB per-CPU. Set them up and map them
unencrypted.

 [ bp: Touchups and simplification. ]

Signed-off-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-42-joro@8bytes.org
parent 1aa9aa8e

arch/x86/include/asm/mem_encrypt.h

+2 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ 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);
@@ -72,6 +73,7 @@ static inline void __init sme_early_init(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; }

arch/x86/kernel/sev-es.c

+55 −1
Original line number Diff line number Diff line
@@ -8,8 +8,13 @@ 
 */



#include <linux/sched/debug.h>	/* For show_regs() */

#include <linux/kernel.h>

#include <linux/percpu-defs.h>

#include <linux/mem_encrypt.h>

#include <linux/printk.h>

#include <linux/mm_types.h>

#include <linux/set_memory.h>

#include <linux/memblock.h>

#include <linux/kernel.h>

#include <linux/mm.h>



#include <asm/sev-es.h>
@@ -29,6 +34,13 @@ static struct ghcb boot_ghcb_page __bss_decrypted __aligned(PAGE_SIZE); 
 */

static struct ghcb __initdata *boot_ghcb;



/* #VC handler runtime per-CPU data */

struct sev_es_runtime_data {

	struct ghcb ghcb_page;

};



static DEFINE_PER_CPU(struct sev_es_runtime_data*, runtime_data);



/* Needed in vc_early_forward_exception */

void do_early_exception(struct pt_regs *regs, int trapnr);
@@ -198,6 +210,48 @@ static bool __init sev_es_setup_ghcb(void) 
	return true;

}



static void __init alloc_runtime_data(int cpu)

{

	struct sev_es_runtime_data *data;



	data = memblock_alloc(sizeof(*data), PAGE_SIZE);

	if (!data)

		panic("Can't allocate SEV-ES runtime data");



	per_cpu(runtime_data, cpu) = data;

}



static void __init init_ghcb(int cpu)

{

	struct sev_es_runtime_data *data;

	int err;



	data = per_cpu(runtime_data, cpu);



	err = early_set_memory_decrypted((unsigned long)&data->ghcb_page,

					 sizeof(data->ghcb_page));

	if (err)

		panic("Can't map GHCBs unencrypted");



	memset(&data->ghcb_page, 0, sizeof(data->ghcb_page));

}



void __init sev_es_init_vc_handling(void)

{

	int cpu;



	BUILD_BUG_ON(offsetof(struct sev_es_runtime_data, ghcb_page) % PAGE_SIZE);



	if (!sev_es_active())

		return;



	/* Initialize per-cpu GHCB pages */

	for_each_possible_cpu(cpu) {

		alloc_runtime_data(cpu);

		init_ghcb(cpu);

	}

}



static void __init vc_early_forward_exception(struct es_em_ctxt *ctxt)

{

	int trapnr = ctxt->fi.vector;

arch/x86/kernel/traps.c

+3 −0
Original line number Diff line number Diff line
@@ -1074,6 +1074,9 @@ void __init trap_init(void) 
	/* Init cpu_entry_area before IST entries are set up */

	setup_cpu_entry_areas();



	/* Init GHCB memory pages when running as an SEV-ES guest */

	sev_es_init_vc_handling();



	idt_setup_traps();



	/*