From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39734) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gWp2a-00047T-Fe for qemu-devel@nongnu.org; Tue, 11 Dec 2018 15:54:06 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gWp2Z-0001ni-2m for qemu-devel@nongnu.org; Tue, 11 Dec 2018 15:54:04 -0500 Received: from mx1.redhat.com ([209.132.183.28]:33212) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gWp2Y-0001nD-S4 for qemu-devel@nongnu.org; Tue, 11 Dec 2018 15:54:02 -0500 From: Eduardo Habkost Date: Tue, 11 Dec 2018 18:53:45 -0200 Message-Id: <20181211205346.11118-4-ehabkost@redhat.com> In-Reply-To: <20181211205346.11118-1-ehabkost@redhat.com> References: <20181211205346.11118-1-ehabkost@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PULL 3/4] target/i386/kvm.c: Don't mark cpuid_data as QEMU_PACKED List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell , qemu-devel@nongnu.org Cc: Paolo Bonzini , kvm@vger.kernel.org, Eduardo Habkost , Marcel Apfelbaum , Richard Henderson , "Michael S. Tsirkin" , Marcelo Tosatti From: Peter Maydell clang complains about taking the address of a packed member of a struct: target/i386/kvm.c:1245:27: warning: taking address of packed member 'cpui= d' of class or structure '' may result in an unaligned pointer value [-Wa= ddress-of-packed-member] c =3D cpuid_find_entry(&cpuid_data.cpuid, 1, 0); ^~~~~~~~~~~~~~~~ target/i386/kvm.c:1297:31: warning: taking address of packed member 'cpui= d' of class or structure '' may result in an unaligned pointer value [-Wa= ddress-of-packed-member] c =3D cpuid_find_entry(&cpuid_data.cpuid, kvm_base, 0); ^~~~~~~~~~~~~~~~ The kernel's definitions of struct kvm_cpuid2 and struct kvm_cpuid_entry2 are carefully set up with padding fields so that there is no between-struct padding anyway, so the QEMU_PACKED annotation is unnecessary and might result in the compiler generating worse code. Drop it, and instead assert at build time that there is no stray padding. Signed-off-by: Peter Maydell Message-Id: <20181210114654.31433-1-peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daud=C3=A9 Reviewed-by: Richard Henderson Signed-off-by: Eduardo Habkost --- target/i386/kvm.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/target/i386/kvm.c b/target/i386/kvm.c index b2401d13ea..739cf8c8ea 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -864,7 +864,15 @@ int kvm_arch_init_vcpu(CPUState *cs) struct { struct kvm_cpuid2 cpuid; struct kvm_cpuid_entry2 entries[KVM_MAX_CPUID_ENTRIES]; - } QEMU_PACKED cpuid_data; + } cpuid_data; + /* + * The kernel defines these structs with padding fields so there + * should be no extra padding in our cpuid_data struct. + */ + QEMU_BUILD_BUG_ON(sizeof(cpuid_data) !=3D + sizeof(struct kvm_cpuid2) + + sizeof(struct kvm_cpuid_entry2) * KVM_MAX_CPUID_EN= TRIES); + X86CPU *cpu =3D X86_CPU(cs); CPUX86State *env =3D &cpu->env; uint32_t limit, i, j, cpuid_i; --=20 2.18.0.rc1.1.g3f1ff2140