* Re: [PATCH v1] x86/vmware: use unsigned integer for shifting
[not found] <20220520114712.595583-1-sshedi@vmware.com>
@ 2022-05-20 11:52 ` Borislav Petkov
[not found] ` <f05264ce-e90f-0b1a-4796-ec1f3b75c09c@gmail.com>
0 siblings, 1 reply; 2+ messages in thread
From: Borislav Petkov @ 2022-05-20 11:52 UTC (permalink / raw)
To: Shreenidhi Shedi
Cc: x86, amakhalov, Shreenidhi Shedi, pv-drivers, dave.hansen,
linux-kernel, virtualization, mingo, hpa, tglx
On Fri, May 20, 2022 at 05:17:12PM +0530, Shreenidhi Shedi wrote:
> Shifting signed 32-bit value by 31 bits is implementation-defined
> behaviour. Using unsigned is better option for this.
>
> Fixes: 4cca6ea04d31 ("x86/apic: Allow x2apic without IR on VMware platform")
>
> Signed-off-by: Shreenidhi Shedi <sshedi@vmware.com>
> Signed-off-by: Shreenidhi Shedi <yesshedi@gmail.com>
This is not how this is done - you need to set your author email
properly in git so that it adds your From: ... @vmware.com> instead of
having two SOBs.
> ---
> arch/x86/kernel/cpu/vmware.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
> index c04b933f48d3..7f44ea073436 100644
> --- a/arch/x86/kernel/cpu/vmware.c
> +++ b/arch/x86/kernel/cpu/vmware.c
> @@ -28,6 +28,7 @@
> #include <linux/cpu.h>
> #include <linux/reboot.h>
> #include <linux/static_call.h>
> +#include <linux/bits.h>
> #include <asm/div64.h>
> #include <asm/x86_init.h>
> #include <asm/hypervisor.h>
> @@ -476,8 +477,8 @@ 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 &&
> - (eax & (1 << VMWARE_CMD_LEGACY_X2APIC)) != 0;
> + return (eax & BIT(VMWARE_CMD_VCPU_RESERVED)) == 0 &&
> + (eax & BIT(VMWARE_CMD_LEGACY_X2APIC)) != 0;
^^^^^^^^
You did hurry too much with sending a new version.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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