[PATCH v4 44/75] x86/sev-es: Allocate and setup IST entry for #VC

Joerg Roedel
2020-07-14T12:14:22Z

From: Joerg Roedel <jroedel@suse.de>

Allocate IST entry number 4 for the #VC handler and setup it up in the
per-cpu TSS. This will setup the TSS for all CPUs before they even
start, so that the boot-code for secondary CPUs can handle #VC
exceptions.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
arch/x86/include/asm/page_64_types.h | 1 +
arch/x86/kernel/sev-es.c | 5 +++++
2 files changed, 6 insertions(+)

diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h
index 288b065955b7..d0c6c10c18a0 100644
--- a/arch/x86/include/asm/page_64_types.h
+++ b/arch/x86/include/asm/page_64_types.h
@@ -28,6 +28,7 @@
#define IST_INDEX_NMI 1
#define IST_INDEX_DB 2
#define IST_INDEX_MCE 3
+#define IST_INDEX_VC 4

/*
* Set __PAGE_OFFSET to the most negative possible address +
diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c
index 64002d86a237..d415368f16ec 100644
--- a/arch/x86/kernel/sev-es.c
+++ b/arch/x86/kernel/sev-es.c
@@ -56,11 +56,13 @@ static void __init sev_es_setup_vc_stacks(int cpu)
{
struct sev_es_runtime_data *data;
struct cpu_entry_area *cea;
+ struct tss_struct *tss;
unsigned long vaddr;
phys_addr_t pa;

data = per_cpu(runtime_data, cpu);
cea = get_cpu_entry_area(cpu);
+ tss = per_cpu_ptr(&cpu_tss_rw, cpu);

/* Map #VC IST stack */
vaddr = CEA_ESTACK_BOT(&cea->estacks, VC);
@@ -71,6 +73,9 @@ static void __init sev_es_setup_vc_stacks(int cpu)
vaddr = CEA_ESTACK_BOT(&cea->estacks, VC2);
pa = __pa(data->fallback_stack);
cea_set_pte((void *)vaddr, pa, PAGE_KERNEL);
+
+ /* Set IST entry in TSS */
+ tss->x86_tss.ist[IST_INDEX_VC] = CEA_ESTACK_TOP(&cea->estacks, VC);
}

/* Needed in vc_early_forward_exception */
--
2.27.0