[tip: x86/vmware] x86/vmware: Use BIT() macro for shifting

From: tip-bot2 for Shreenidhi Shedi
Date: Wed Jun 22 2022 - 05:42:44 EST


The following commit has been merged into the x86/vmware branch of tip:

Commit-ID: 4745ca43104b422354f06dc814d3f13661f217af
Gitweb: https://git.kernel.org/tip/4745ca43104b422354f06dc814d3f13661f217af
Author: Shreenidhi Shedi <sshedi@xxxxxxxxxx>
AuthorDate: Wed, 01 Jun 2022 15:48:20 +05:30
Committer: Borislav Petkov <bp@xxxxxxx>
CommitterDate: Wed, 22 Jun 2022 11:23:14 +02:00

x86/vmware: Use BIT() macro for shifting

VMWARE_CMD_VCPU_RESERVED is bit 31 and that would mean undefined
behavior when shifting an int but the kernel is built with
-fno-strict-overflow which will wrap around using two's complement.

Use the BIT() macro to improve readability and avoid any potential
overflow confusion because it uses an unsigned long.

[ bp: Clarify commit message. ]

Signed-off-by: Shreenidhi Shedi <sshedi@xxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Srivatsa S. Bhat (VMware) <srivatsa@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220601101820.535031-1-sshedi@xxxxxxxxxx
---
arch/x86/kernel/cpu/vmware.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index c04b933..02039ec 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -476,8 +476,8 @@ 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)) &&
+ (eax & BIT(VMWARE_CMD_LEGACY_X2APIC));
}

#ifdef CONFIG_AMD_MEM_ENCRYPT