linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Colin King <colin.king@canonical.com>
To: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Sean Christopherson" <sean.j.christopherson@intel.com>,
	"Vitaly Kuznetsov" <vkuznets@redhat.com>,
	"Wanpeng Li" <wanpengli@tencent.com>,
	"Jim Mattson" <jmattson@google.com>,
	"Joerg Roedel" <joro@8bytes.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"H . Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, kvm@vger.kernel.org,
	clang-built-linux@googlegroups.com
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] KVM: x86/mmu: fix comparison of u8 with -1
Date: Tue, 26 Nov 2019 16:12:55 +0000	[thread overview]
Message-ID: <20191126161255.323992-1-colin.king@canonical.com> (raw)

From: Colin Ian King <colin.king@canonical.com>

The comparison of the u8 value __entry->u with -1 is always
going to be false because a __entry-u can never be negative.
Fix this by casting it to a s8 integer.

Addresses clang warning:
arch/x86/kvm/./mmutrace.h:360:16: warning: result of comparison
of constant -1 with expression of type 'u8' (aka 'unsigned char')
is always false [-Wtautological-constant-out-of-range-compare]

Fixes: 335e192a3fa4 ("KVM: x86: add tracepoints around __direct_map and FNAME(fetch)")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 arch/x86/kvm/mmutrace.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmutrace.h b/arch/x86/kvm/mmutrace.h
index 7ca8831c7d1a..3466cd528a67 100644
--- a/arch/x86/kvm/mmutrace.h
+++ b/arch/x86/kvm/mmutrace.h
@@ -357,7 +357,7 @@ TRACE_EVENT(
 		  __entry->r ? "r" : "-",
 		  __entry->spte & PT_WRITABLE_MASK ? "w" : "-",
 		  __entry->x ? "x" : "-",
-		  __entry->u == -1 ? "" : (__entry->u ? "u" : "-"),
+		  (s8)__entry->u == -1 ? "" : (__entry->u ? "u" : "-"),
 		  __entry->level, __entry->sptep
 	)
 );
-- 
2.24.0


             reply	other threads:[~2019-11-26 16:21 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-26 16:12 Colin King [this message]
2019-11-26 17:24 ` [PATCH] KVM: x86/mmu: fix comparison of u8 with -1 Nick Desaulniers
2019-11-27  2:21 linmiaohe

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=20191126161255.323992-1-colin.king@canonical.com \
    --to=colin.king@canonical.com \
    --cc=bp@alien8.de \
    --cc=clang-built-linux@googlegroups.com \
    --cc=hpa@zytor.com \
    --cc=jmattson@google.com \
    --cc=joro@8bytes.org \
    --cc=kernel-janitors@vger.kernel.org \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@redhat.com \
    --cc=pbonzini@redhat.com \
    --cc=rkrcmar@redhat.com \
    --cc=sean.j.christopherson@intel.com \
    --cc=tglx@linutronix.de \
    --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).