From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org
Cc: Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
"H. Peter Anvin" <hpa@zytor.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
"David P . Reed" <dpreed@deepplum.com>,
Randy Dunlap <rdunlap@infradead.org>,
Uros Bizjak <ubizjak@gmail.com>
Subject: [PATCH 7/9] KVM: SVM: Use asm goto to handle unexpected #UD on SVM instructions
Date: Wed, 30 Dec 2020 16:27:00 -0800 [thread overview]
Message-ID: <20201231002702.2223707-8-seanjc@google.com> (raw)
In-Reply-To: <20201231002702.2223707-1-seanjc@google.com>
Add svm_asm*() macros, a la the existing vmx_asm*() macros, to handle
faults on SVM instructions instead of using the generic __ex(), a.k.a.
__kvm_handle_fault_on_reboot(). Using asm goto generates slightly
better code as it eliminates the in-line JMP+CALL sequences that are
needed by __kvm_handle_fault_on_reboot() to avoid triggering BUG()
from fixup (which generates bad stack traces).
Using SVM specific macros also drops the last user of __ex() and the
the last asm linkage to kvm_spurious_fault(), and adds a helper for
VMSAVE, which may gain an addition call site in the future (as part
of optimizing the SVM context switching).
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/svm/sev.c | 3 +-
arch/x86/kvm/svm/svm.c | 16 +----------
arch/x86/kvm/svm/svm_ops.h | 59 ++++++++++++++++++++++++++++++++++++++
3 files changed, 62 insertions(+), 16 deletions(-)
create mode 100644 arch/x86/kvm/svm/svm_ops.h
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 9858d5ae9ddd..4511d7ccdb19 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -22,6 +22,7 @@
#include "x86.h"
#include "svm.h"
+#include "svm_ops.h"
#include "cpuid.h"
#include "trace.h"
@@ -2001,7 +2002,7 @@ void sev_es_vcpu_load(struct vcpu_svm *svm, int cpu)
* of which one step is to perform a VMLOAD. Since hardware does not
* perform a VMSAVE on VMRUN, the host savearea must be updated.
*/
- asm volatile(__ex("vmsave") : : "a" (__sme_page_pa(sd->save_area)) : "memory");
+ vmsave(__sme_page_pa(sd->save_area));
/*
* Certain MSRs are restored on VMEXIT, only save ones that aren't
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index cce0143a6f80..4308ab5ca27e 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -41,6 +41,7 @@
#include "trace.h"
#include "svm.h"
+#include "svm_ops.h"
#define __ex(x) __kvm_handle_fault_on_reboot(x)
@@ -246,21 +247,6 @@ u32 svm_msrpm_offset(u32 msr)
#define MAX_INST_SIZE 15
-static inline void clgi(void)
-{
- asm volatile (__ex("clgi"));
-}
-
-static inline void stgi(void)
-{
- asm volatile (__ex("stgi"));
-}
-
-static inline void invlpga(unsigned long addr, u32 asid)
-{
- asm volatile (__ex("invlpga %1, %0") : : "c"(asid), "a"(addr));
-}
-
static int get_max_npt_level(void)
{
#ifdef CONFIG_X86_64
diff --git a/arch/x86/kvm/svm/svm_ops.h b/arch/x86/kvm/svm/svm_ops.h
new file mode 100644
index 000000000000..0c8377aee52c
--- /dev/null
+++ b/arch/x86/kvm/svm/svm_ops.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __KVM_X86_SVM_OPS_H
+#define __KVM_X86_SVM_OPS_H
+
+#include <linux/compiler_types.h>
+
+#include <asm/kvm_host.h>
+
+#define svm_asm(insn, clobber...) \
+do { \
+ asm_volatile_goto("1: " __stringify(insn) "\n\t" \
+ _ASM_EXTABLE(1b, %l[fault]) \
+ ::: clobber : fault); \
+ return; \
+fault: \
+ kvm_spurious_fault(); \
+} while (0)
+
+#define svm_asm1(insn, op1, clobber...) \
+do { \
+ asm_volatile_goto("1: " __stringify(insn) " %0\n\t" \
+ _ASM_EXTABLE(1b, %l[fault]) \
+ :: op1 : clobber : fault); \
+ return; \
+fault: \
+ kvm_spurious_fault(); \
+} while (0)
+
+#define svm_asm2(insn, op1, op2, clobber...) \
+do { \
+ asm_volatile_goto("1: " __stringify(insn) " %1, %0\n\t" \
+ _ASM_EXTABLE(1b, %l[fault]) \
+ :: op1, op2 : clobber : fault); \
+ return; \
+fault: \
+ kvm_spurious_fault(); \
+} while (0)
+
+static inline void clgi(void)
+{
+ svm_asm(clgi);
+}
+
+static inline void stgi(void)
+{
+ svm_asm(stgi);
+}
+
+static inline void invlpga(unsigned long addr, u32 asid)
+{
+ svm_asm2(invlpga, "c"(asid), "a"(addr));
+}
+
+static inline void vmsave(hpa_t pa)
+{
+ svm_asm1(vmsave, "a" (pa), "memory");
+}
+
+#endif /* __KVM_X86_SVM_OPS_H */
--
2.29.2.729.g45daf8777d-goog
next prev parent reply other threads:[~2020-12-31 0:29 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-31 0:26 [PATCH 0/9] x86/virt: KVM: x86: Exception handling fixes/cleanups Sean Christopherson
2020-12-31 0:26 ` [PATCH 1/9] x86/virt: Eat faults on VMXOFF in reboot flows Sean Christopherson
2020-12-31 0:26 ` [PATCH 2/9] x86/reboot: Force all cpus to exit VMX root if VMX is supported Sean Christopherson
2020-12-31 0:26 ` [PATCH 3/9] x86/virt: Mark flags and memory as clobbered by VMXOFF Sean Christopherson
2020-12-31 0:26 ` [PATCH 4/9] KVM/nVMX: Use __vmx_vcpu_run in nested_vmx_check_vmentry_hw Sean Christopherson
2020-12-31 0:26 ` [PATCH 5/9] KVM: VMX: Move Intel PT shenanigans out of VMXON/VMXOFF flows Sean Christopherson
2020-12-31 0:26 ` [PATCH 6/9] KVM: VMX: Use the kernel's version of VMXOFF Sean Christopherson
2020-12-31 0:27 ` Sean Christopherson [this message]
2020-12-31 0:27 ` [PATCH 8/9] KVM: x86: Kill off __ex() and __kvm_handle_fault_on_reboot() Sean Christopherson
2020-12-31 0:27 ` [PATCH 9/9] KVM: x86: Move declaration of kvm_spurious_fault() to x86.h Sean Christopherson
2021-01-27 17:26 ` [PATCH 0/9] x86/virt: KVM: x86: Exception handling fixes/cleanups Paolo Bonzini
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201231002702.2223707-8-seanjc@google.com \
--to=seanjc@google.com \
--cc=bp@alien8.de \
--cc=dpreed@deepplum.com \
--cc=hpa@zytor.com \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=rdunlap@infradead.org \
--cc=tglx@linutronix.de \
--cc=ubizjak@gmail.com \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).