Re: [PATCH] x86/cpufeatures: Force disable X86_FEATURE_ENQCMD and remove update_pasid()
From: Borislav Petkov <bp@alien8.de>
Date: 2021-06-02 10:14:17
Also in:
linux-iommu, lkml
Subsystem:
dma generic offload engine subsystem, intel idxd driver, the rest · Maintainers:
Vinod Koul, Vinicius Costa Gomes, Linus Torvalds
On Sat, May 29, 2021 at 11:17:30AM +0200, Thomas Gleixner wrote:
quoted hunk
--- a/arch/x86/include/asm/disabled-features.h +++ b/arch/x86/include/asm/disabled-features.h@@ -56,11 +56,8 @@ # define DISABLE_PTI (1 << (X86_FEATURE_PTI & 31)) #endif -#ifdef CONFIG_IOMMU_SUPPORT -# define DISABLE_ENQCMD 0 -#else -# define DISABLE_ENQCMD (1 << (X86_FEATURE_ENQCMD & 31)) -#endif +/* Force disable because it's broken beyond repair */ +#define DISABLE_ENQCMD (1 << (X86_FEATURE_ENQCMD & 31))
Yeah, for that to work we need:
---
From: Borislav Petkov <redacted>
Date: Wed, 2 Jun 2021 12:07:52 +0200
Subject: [PATCH] dmaengine: idxd: Use cpu_feature_enabled()
When testing x86 feature bits, use cpu_feature_enabled() so that
build-disabled features can remain off, regardless of what CPUID says.
Fixes: 8e50d392652f ("dmaengine: idxd: Add shared workqueue support")
Signed-off-by: Borislav Petkov <redacted>
Cc: <redacted>
---
drivers/dma/idxd/init.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 2a926bef87f2..776fd44aff5f 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c@@ -745,12 +745,12 @@ static int __init idxd_init_module(void) * If the CPU does not support MOVDIR64B or ENQCMDS, there's no point in * enumerating the device. We can not utilize it. */ - if (!boot_cpu_has(X86_FEATURE_MOVDIR64B)) { + if (!cpu_feature_enabled(X86_FEATURE_MOVDIR64B)) { pr_warn("idxd driver failed to load without MOVDIR64B.\n"); return -ENODEV; } - if (!boot_cpu_has(X86_FEATURE_ENQCMD)) + if (!cpu_feature_enabled(X86_FEATURE_ENQCMD)) pr_warn("Platform does not have ENQCMD(S) support.\n"); else support_enqcmd = true;
--
2.29.2
For the newly CCed parties, pls check
https://lkml.kernel.org/r/87mtsd6gr9.ffs@nanos.tec.linutronix.de
for more info.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette