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

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Message-Id: <20200714120917.11253-45-joro@8bytes.org>
Date:   Tue, 14 Jul 2020 14:08:46 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     x86@...nel.org
Cc:     Joerg Roedel <joro@...tes.org>, Joerg Roedel <jroedel@...e.de>,
        hpa@...or.com, Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Jiri Slaby <jslaby@...e.cz>,
        Dan Williams <dan.j.williams@...el.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Juergen Gross <jgross@...e.com>,
        Kees Cook <keescook@...omium.org>,
        David Rientjes <rientjes@...gle.com>,
        Cfir Cohen <cfir@...gle.com>,
        Erdem Aktas <erdemaktas@...gle.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Mike Stunes <mstunes@...are.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Martin Radev <martin.b.radev@...il.com>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        virtualization@...ts.linux-foundation.org
Subject: [PATCH v4 44/75] x86/sev-es: Allocate and setup IST entry for #VC

From: Joerg Roedel <jroedel@...e.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@...e.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