From: Joerg Roedel <joro@8bytes.org>
To: x86@kernel.org
Cc: Joerg Roedel <joro@8bytes.org>, Joerg Roedel <jroedel@suse.de>,
stable@vger.kernel.org, hpa@zytor.com,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Jiri Slaby <jslaby@suse.cz>,
Dan Williams <dan.j.williams@intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Juergen Gross <jgross@suse.com>,
Kees Cook <keescook@chromium.org>,
David Rientjes <rientjes@google.com>,
Cfir Cohen <cfir@google.com>, Erdem Aktas <erdemaktas@google.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mike Stunes <mstunes@vmware.com>,
Sean Christopherson <seanjc@google.com>,
Martin Radev <martin.b.radev@gmail.com>,
Arvind Sankar <nivedita@alum.mit.edu>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
virtualization@lists.linux-foundation.org
Subject: [PATCH 1/3] x86/sev-es: Introduce from_syscall_gap() helper
Date: Wed, 17 Feb 2021 13:01:41 +0100 [thread overview]
Message-ID: <20210217120143.6106-2-joro@8bytes.org> (raw)
In-Reply-To: <20210217120143.6106-1-joro@8bytes.org>
From: Joerg Roedel <jroedel@suse.de>
Introduce a helper to check whether an exception came from the syscall
gap and use it in the SEV-ES code
Fixes: 315562c9af3d5 ("x86/sev-es: Adjust #VC IST Stack on entering NMI handler")
Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
arch/x86/include/asm/ptrace.h | 8 ++++++++
arch/x86/kernel/traps.c | 3 +--
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index d8324a236696..14854b2c4944 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -94,6 +94,8 @@ struct pt_regs {
#include <asm/paravirt_types.h>
#endif
+#include <asm/proto.h>
+
struct cpuinfo_x86;
struct task_struct;
@@ -175,6 +177,12 @@ static inline bool any_64bit_mode(struct pt_regs *regs)
#ifdef CONFIG_X86_64
#define current_user_stack_pointer() current_pt_regs()->sp
#define compat_user_stack_pointer() current_pt_regs()->sp
+
+static inline bool from_syscall_gap(struct pt_regs *regs)
+{
+ return (regs->ip >= (unsigned long)entry_SYSCALL_64 &&
+ regs->ip < (unsigned long)entry_SYSCALL_64_safe_stack);
+}
#endif
static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 7f5aec758f0e..b4f2b4e9066d 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -694,8 +694,7 @@ asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *r
* In the SYSCALL entry path the RSP value comes from user-space - don't
* trust it and switch to the current kernel stack
*/
- if (regs->ip >= (unsigned long)entry_SYSCALL_64 &&
- regs->ip < (unsigned long)entry_SYSCALL_64_safe_stack) {
+ if (from_syscall_gap(regs)) {
sp = this_cpu_read(cpu_current_top_of_stack);
goto sync;
}
--
2.30.0
next prev parent reply other threads:[~2021-02-17 12:07 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-17 12:01 [PATCH 0/3] x86/sev-es: Check for trusted regs->sp in __sev_es_ist_enter() Joerg Roedel
2021-02-17 12:01 ` Joerg Roedel [this message]
2021-02-17 17:59 ` [PATCH 1/3] x86/sev-es: Introduce from_syscall_gap() helper Borislav Petkov
2021-02-17 12:01 ` [PATCH 2/3] x86/sev-es: Check if regs->sp is trusted before adjusting #VC IST stack Joerg Roedel
2021-02-17 18:00 ` Borislav Petkov
2021-02-17 18:09 ` Andy Lutomirski
2021-02-18 11:25 ` Joerg Roedel
2021-02-18 17:49 ` Andy Lutomirski
2021-02-18 19:21 ` Joerg Roedel
2021-02-19 0:28 ` Andy Lutomirski
2021-02-19 11:05 ` Joerg Roedel
2021-02-17 12:01 ` [PATCH 3/3] x86/sev-es: Improve comments in and around __sev_es_ist_enter/exit() Joerg Roedel
2021-02-17 18:00 ` Borislav Petkov
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