some 5.4 experiments for warning messages

[thirdparty/kernel/stable-queue.git] / pending / 5.4 / x86-xen-kvm-gather-the-definition-of-emulate-prefixes.patch

diff --git a/pending/5.4/x86-xen-kvm-gather-the-definition-of-emulate-prefixes.patch b/pending/5.4/x86-xen-kvm-gather-the-definition-of-emulate-prefixes.patch
new file mode 100644 (file)
index 0000000..e2b5159
--- /dev/null
+++ b/pending/5.4/x86-xen-kvm-gather-the-definition-of-emulate-prefixes.patch
@@ -0,0 +1,98 @@
+From b3dc0695fa40c3b280230fb6fb7fb7a94ce28bf4 Mon Sep 17 00:00:00 2001
+From: Masami Hiramatsu <mhiramat@kernel.org>
+Date: Fri, 6 Sep 2019 22:13:59 +0900
+Subject: x86: xen: kvm: Gather the definition of emulate prefixes
+
+From: Masami Hiramatsu <mhiramat@kernel.org>
+
+commit b3dc0695fa40c3b280230fb6fb7fb7a94ce28bf4 upstream.
+
+Gather the emulate prefixes, which forcibly make the following
+instruction emulated on virtualization, in one place.
+
+Suggested-by: Peter Zijlstra <peterz@infradead.org>
+Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Cc: Juergen Gross <jgross@suse.com>
+Cc: x86@kernel.org
+Cc: Ingo Molnar <mingo@kernel.org>
+Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
+Cc: Andrew Cooper <andrew.cooper3@citrix.com>
+Cc: Stefano Stabellini <sstabellini@kernel.org>
+Cc: Borislav Petkov <bp@alien8.de>
+Cc: xen-devel@lists.xenproject.org
+Cc: Randy Dunlap <rdunlap@infradead.org>
+Cc: Josh Poimboeuf <jpoimboe@redhat.com>
+Link: https://lkml.kernel.org/r/156777563917.25081.7286628561790289995.stgit@devnote2
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+diff --git a/arch/x86/include/asm/emulate_prefix.h b/arch/x86/include/asm/emulate_prefix.h
+new file mode 100644
+index 000000000000..70f5b98a5286
+--- /dev/null
++++ b/arch/x86/include/asm/emulate_prefix.h
+@@ -0,0 +1,14 @@
++/* SPDX-License-Identifier: GPL-2.0 */
++#ifndef _ASM_X86_EMULATE_PREFIX_H
++#define _ASM_X86_EMULATE_PREFIX_H
++
++/*
++ * Virt escape sequences to trigger instruction emulation;
++ * ideally these would decode to 'whole' instruction and not destroy
++ * the instruction stream; sadly this is not true for the 'kvm' one :/
++ */
++
++#define __XEN_EMULATE_PREFIX  0x0f,0x0b,0x78,0x65,0x6e  /* ud2 ; .ascii "xen" */
++#define __KVM_EMULATE_PREFIX  0x0f,0x0b,0x6b,0x76,0x6d        /* ud2 ; .ascii "kvm" */
++
++#endif
+diff --git a/arch/x86/include/asm/xen/interface.h b/arch/x86/include/asm/xen/interface.h
+index 62ca03ef5c65..9139b3e86316 100644
+--- a/arch/x86/include/asm/xen/interface.h
++++ b/arch/x86/include/asm/xen/interface.h
+@@ -379,12 +379,9 @@ struct xen_pmu_arch {
+  * Prefix forces emulation of some non-trapping instructions.
+  * Currently only CPUID.
+  */
+-#ifdef __ASSEMBLY__
+-#define XEN_EMULATE_PREFIX .byte 0x0f,0x0b,0x78,0x65,0x6e ;
+-#define XEN_CPUID          XEN_EMULATE_PREFIX cpuid
+-#else
+-#define XEN_EMULATE_PREFIX ".byte 0x0f,0x0b,0x78,0x65,0x6e ; "
+-#define XEN_CPUID          XEN_EMULATE_PREFIX "cpuid"
+-#endif
++#include <asm/emulate_prefix.h>
++
++#define XEN_EMULATE_PREFIX __ASM_FORM(.byte __XEN_EMULATE_PREFIX ;)
++#define XEN_CPUID          XEN_EMULATE_PREFIX __ASM_FORM(cpuid)
+ 
+ #endif /* _ASM_X86_XEN_INTERFACE_H */
+diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
+index 661e2bf38526..777574f547c0 100644
+--- a/arch/x86/kvm/x86.c
++++ b/arch/x86/kvm/x86.c
+@@ -68,6 +68,7 @@
+ #include <asm/mshyperv.h>
+ #include <asm/hypervisor.h>
+ #include <asm/intel_pt.h>
++#include <asm/emulate_prefix.h>
+ #include <clocksource/hyperv_timer.h>
+ 
+ #define CREATE_TRACE_POINTS
+@@ -5446,6 +5447,7 @@ EXPORT_SYMBOL_GPL(kvm_write_guest_virt_system);
+ 
+ int handle_ud(struct kvm_vcpu *vcpu)
+ {
++      static const char kvm_emulate_prefix[] = { __KVM_EMULATE_PREFIX };
+       int emul_type = EMULTYPE_TRAP_UD;
+       char sig[5]; /* ud2; .ascii "kvm" */
+       struct x86_exception e;
+@@ -5453,7 +5455,7 @@ int handle_ud(struct kvm_vcpu *vcpu)
+       if (force_emulation_prefix &&
+           kvm_read_guest_virt(vcpu, kvm_get_linear_rip(vcpu),
+                               sig, sizeof(sig), &e) == 0 &&
+-          memcmp(sig, "\xf\xbkvm", sizeof(sig)) == 0) {
++          memcmp(sig, kvm_emulate_prefix, sizeof(sig)) == 0) {
+               kvm_rip_write(vcpu, kvm_rip_read(vcpu) + sizeof(sig));
+               emul_type = EMULTYPE_TRAP_UD_FORCED;
+       }