lkml.org 
[lkml]   [2020]   [Sep]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip: x86/seves] x86/sev-es: Setup per-CPU GHCBs for the runtime handler
The following commit has been merged into the x86/seves branch of tip:

Commit-ID: 885689e47dfa1499b756a07237eb645234d93cf9
Gitweb: https://git.kernel.org/tip/885689e47dfa1499b756a07237eb645234d93cf9
Author: Tom Lendacky <thomas.lendacky@amd.com>
AuthorDate: Mon, 07 Sep 2020 15:15:42 +02:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Wed, 09 Sep 2020 11:33:19 +02:00

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
---
arch/x86/include/asm/mem_encrypt.h | 2 +-
arch/x86/kernel/sev-es.c | 56 ++++++++++++++++++++++++++++-
arch/x86/kernel/traps.c | 3 ++-
3 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 4e72b73..c9f5df0 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -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; }
diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c
index 213a427..720b1b6 100644
--- a/arch/x86/kernel/sev-es.c
+++ b/arch/x86/kernel/sev-es.c
@@ -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;
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 81a2fb7..2dc32b0 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -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();

/*
\
 
 \ /
  Last update: 2020-09-10 11:39    [W:0.409 / U:1.112 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site