From: Borislav Petkov <bp@alien8.de>
To: Shreenidhi Shedi <yesshedi@gmail.com>
Cc: srivatsa@csail.mit.edu, amakhalov@vmware.com, tglx@linutronix.de,
mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com,
virtualization@lists.linux-foundation.org, pv-drivers@vmware.com,
x86@kernel.org, linux-kernel@vger.kernel.org,
Shreenidhi Shedi <sshedi@vmware.com>
Subject: Re: [PATCH] x86/vmware: use unsigned integer for shifting
Date: Fri, 20 May 2022 11:26:54 +0200 [thread overview]
Message-ID: <Yode3m6iia9ZBHsl@zn.tnic> (raw)
In-Reply-To: <20220520072857.592746-1-sshedi@vmware.com>
On Fri, May 20, 2022 at 12:58:57PM +0530, Shreenidhi Shedi wrote:
> Shifting signed 32-bit value by 31 bits is implementation-defined
> behaviour. Using unsigned is better option for this.
>
> Signed-off-by: Shreenidhi Shedi <sshedi@vmware.com>
> ---
> arch/x86/kernel/cpu/vmware.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
> index c04b933f48d3..b28f789d3c56 100644
> --- a/arch/x86/kernel/cpu/vmware.c
> +++ b/arch/x86/kernel/cpu/vmware.c
> @@ -476,7 +476,7 @@ static bool __init vmware_legacy_x2apic_available(void)
> {
> uint32_t eax, ebx, ecx, edx;
> VMWARE_CMD(GETVCPU_INFO, eax, ebx, ecx, edx);
> - return (eax & (1 << VMWARE_CMD_VCPU_RESERVED)) == 0 &&
> + return (eax & (1U << VMWARE_CMD_VCPU_RESERVED)) == 0 &&
> (eax & (1 << VMWARE_CMD_LEGACY_X2APIC)) != 0;
Or you can use the BIT() macro and simplify this expression even more:
return !(eax & BIT(VMWARE_CMD_VCPU_RESERVED)) &&
(eax & BIT(VMWARE_CMD_LEGACY_X2APIC));
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2022-05-20 9:27 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-20 7:28 [PATCH] x86/vmware: use unsigned integer for shifting Shreenidhi Shedi
2022-05-20 9:26 ` Borislav Petkov [this message]
2022-05-20 11:29 ` Srivatsa S. Bhat
2022-05-20 11:42 ` Shreenidhi Shedi
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