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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: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-42-joro@8bytes.org
This commit is contained in:
Tom Lendacky 2020-09-07 15:15:42 +02:00 committed by Borislav Petkov
parent 1aa9aa8ee5
commit 885689e47d
3 changed files with 60 additions and 1 deletions
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2
arch/x86/include/asm/mem_encrypt.h
View File

@ -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; }

56
arch/x86/kernel/sev-es.c
View File

@ -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;

3
arch/x86/kernel/traps.c
View File

@ -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();
/*