* [PATCH v2 0/5] x86: Switch X86_FEATURE_XENPV to cpu_feature_enabled() use
@ 2022-11-04 7:26 Juergen Gross
2022-11-04 7:26 ` [PATCH v2 1/5] x86: add X86_FEATURE_XENPV to disabled-features.h Juergen Gross
` (5 more replies)
0 siblings, 6 replies; 17+ messages in thread
From: Juergen Gross @ 2022-11-04 7:26 UTC (permalink / raw)
To: linux-kernel, xen-devel, x86
Cc: Juergen Gross, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, H. Peter Anvin, Andy Lutomirski, Peter Zijlstra,
Pu Wen
Make especially kernels without CONFIG_XEN_PV more efficient by
using cpu_feature_enabled(X86_FEATURE_XENPV) instead of boot_cpu_has()
and friends.
Changes in V2:
- new patch 4
Juergen Gross (5):
x86: add X86_FEATURE_XENPV to disabled-features.h
x86: remove unneeded 64-bit dependency in arch_enter_from_user_mode()
x86: drop 32-bit Xen PV guest code in update_task_stack()
x86: remove X86_FEATURE_XENPV usage in setup_cpu_entry_area()
x86: switch to cpu_feature_enabled() for X86_FEATURE_XENPV
arch/x86/include/asm/disabled-features.h | 8 +++++++-
arch/x86/include/asm/entry-common.h | 4 ++--
arch/x86/include/asm/switch_to.h | 7 ++-----
arch/x86/kernel/cpu/amd.c | 2 +-
arch/x86/kernel/cpu/bugs.c | 2 +-
arch/x86/kernel/cpu/hygon.c | 2 +-
arch/x86/kernel/process_64.c | 4 ++--
arch/x86/kernel/topology.c | 2 +-
arch/x86/mm/cpu_entry_area.c | 8 ++------
9 files changed, 19 insertions(+), 20 deletions(-)
--
2.35.3
^ permalink raw reply [flat|nested] 17+ messages in thread
* [PATCH v2 1/5] x86: add X86_FEATURE_XENPV to disabled-features.h
2022-11-04 7:26 [PATCH v2 0/5] x86: Switch X86_FEATURE_XENPV to cpu_feature_enabled() use Juergen Gross
@ 2022-11-04 7:26 ` Juergen Gross
2022-11-04 14:56 ` Dave Hansen
2022-11-22 18:04 ` [tip: x86/cpu] x86/cpufeatures: Add " tip-bot2 for Juergen Gross
2022-11-04 7:26 ` [PATCH v2 2/5] x86: remove unneeded 64-bit dependency in arch_enter_from_user_mode() Juergen Gross
` (4 subsequent siblings)
5 siblings, 2 replies; 17+ messages in thread
From: Juergen Gross @ 2022-11-04 7:26 UTC (permalink / raw)
To: linux-kernel, xen-devel, x86
Cc: Juergen Gross, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, H. Peter Anvin
Add X86_FEATURE_XENPV to the features handled specially in
disabled-features.h.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/x86/include/asm/disabled-features.h | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index 33d2cd04d254..c862552d7d6d 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -81,6 +81,12 @@
# define DISABLE_SGX (1 << (X86_FEATURE_SGX & 31))
#endif
+#ifdef CONFIG_XEN_PV
+# define DISABLE_XENPV 0
+#else
+# define DISABLE_XENPV (1 << (X86_FEATURE_XENPV & 31))
+#endif
+
#ifdef CONFIG_INTEL_TDX_GUEST
# define DISABLE_TDX_GUEST 0
#else
@@ -98,7 +104,7 @@
#define DISABLED_MASK5 0
#define DISABLED_MASK6 0
#define DISABLED_MASK7 (DISABLE_PTI)
-#define DISABLED_MASK8 (DISABLE_TDX_GUEST)
+#define DISABLED_MASK8 (DISABLE_XENPV|DISABLE_TDX_GUEST)
#define DISABLED_MASK9 (DISABLE_SGX)
#define DISABLED_MASK10 0
#define DISABLED_MASK11 (DISABLE_RETPOLINE|DISABLE_RETHUNK|DISABLE_UNRET)
--
2.35.3
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v2 2/5] x86: remove unneeded 64-bit dependency in arch_enter_from_user_mode()
2022-11-04 7:26 [PATCH v2 0/5] x86: Switch X86_FEATURE_XENPV to cpu_feature_enabled() use Juergen Gross
2022-11-04 7:26 ` [PATCH v2 1/5] x86: add X86_FEATURE_XENPV to disabled-features.h Juergen Gross
@ 2022-11-04 7:26 ` Juergen Gross
2022-11-04 14:58 ` Dave Hansen
2022-11-22 18:04 ` [tip: x86/cpu] x86/cpu: Remove " tip-bot2 for Juergen Gross
2022-11-04 7:26 ` [PATCH v2 3/5] x86: drop 32-bit Xen PV guest code in update_task_stack() Juergen Gross
` (3 subsequent siblings)
5 siblings, 2 replies; 17+ messages in thread
From: Juergen Gross @ 2022-11-04 7:26 UTC (permalink / raw)
To: linux-kernel, xen-devel, x86
Cc: Juergen Gross, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, H. Peter Anvin
The check for 64-bit mode when testing X86_FEATURE_XENPV isn't needed,
as Xen PV guests are no longer supported in 32-bit mode.
While at it switch from boot_cpu_has() to cpu_feature_enabled().
Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/x86/include/asm/entry-common.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/entry-common.h b/arch/x86/include/asm/entry-common.h
index 674ed46d3ced..117903881fe4 100644
--- a/arch/x86/include/asm/entry-common.h
+++ b/arch/x86/include/asm/entry-common.h
@@ -24,8 +24,8 @@ static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs)
/*
* For !SMAP hardware we patch out CLAC on entry.
*/
- if (boot_cpu_has(X86_FEATURE_SMAP) ||
- (IS_ENABLED(CONFIG_64BIT) && boot_cpu_has(X86_FEATURE_XENPV)))
+ if (cpu_feature_enabled(X86_FEATURE_SMAP) ||
+ cpu_feature_enabled(X86_FEATURE_XENPV))
mask |= X86_EFLAGS_AC;
WARN_ON_ONCE(flags & mask);
--
2.35.3
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v2 3/5] x86: drop 32-bit Xen PV guest code in update_task_stack()
2022-11-04 7:26 [PATCH v2 0/5] x86: Switch X86_FEATURE_XENPV to cpu_feature_enabled() use Juergen Gross
2022-11-04 7:26 ` [PATCH v2 1/5] x86: add X86_FEATURE_XENPV to disabled-features.h Juergen Gross
2022-11-04 7:26 ` [PATCH v2 2/5] x86: remove unneeded 64-bit dependency in arch_enter_from_user_mode() Juergen Gross
@ 2022-11-04 7:26 ` Juergen Gross
2022-11-04 15:04 ` Dave Hansen
2022-11-22 18:04 ` [tip: x86/cpu] x86/cpu: Drop " tip-bot2 for Juergen Gross
2022-11-04 7:27 ` [PATCH v2 4/5] x86: remove X86_FEATURE_XENPV usage in setup_cpu_entry_area() Juergen Gross
` (2 subsequent siblings)
5 siblings, 2 replies; 17+ messages in thread
From: Juergen Gross @ 2022-11-04 7:26 UTC (permalink / raw)
To: linux-kernel, xen-devel, x86
Cc: Juergen Gross, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, H. Peter Anvin
Testing for Xen PV guest mode in a 32-bit only code section can be
dropped, as Xen PV guests are supported in 64-bit mode only.
While at it switch from boot_cpu_has() to cpu_feature_enabled() in the
64-bit part of the code.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/x86/include/asm/switch_to.h | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h
index c08eb0fdd11f..5c91305d09d2 100644
--- a/arch/x86/include/asm/switch_to.h
+++ b/arch/x86/include/asm/switch_to.h
@@ -66,13 +66,10 @@ static inline void update_task_stack(struct task_struct *task)
{
/* sp0 always points to the entry trampoline stack, which is constant: */
#ifdef CONFIG_X86_32
- if (static_cpu_has(X86_FEATURE_XENPV))
- load_sp0(task->thread.sp0);
- else
- this_cpu_write(cpu_tss_rw.x86_tss.sp1, task->thread.sp0);
+ this_cpu_write(cpu_tss_rw.x86_tss.sp1, task->thread.sp0);
#else
/* Xen PV enters the kernel on the thread stack. */
- if (static_cpu_has(X86_FEATURE_XENPV))
+ if (cpu_feature_enabled(X86_FEATURE_XENPV))
load_sp0(task_top_of_stack(task));
#endif
}
--
2.35.3
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v2 4/5] x86: remove X86_FEATURE_XENPV usage in setup_cpu_entry_area()
2022-11-04 7:26 [PATCH v2 0/5] x86: Switch X86_FEATURE_XENPV to cpu_feature_enabled() use Juergen Gross
` (2 preceding siblings ...)
2022-11-04 7:26 ` [PATCH v2 3/5] x86: drop 32-bit Xen PV guest code in update_task_stack() Juergen Gross
@ 2022-11-04 7:27 ` Juergen Gross
2022-11-04 15:04 ` Dave Hansen
2022-11-22 18:04 ` [tip: x86/cpu] x86/cpu: Remove " tip-bot2 for Juergen Gross
2022-11-04 7:27 ` [PATCH v2 5/5] x86: switch to cpu_feature_enabled() for X86_FEATURE_XENPV Juergen Gross
2022-11-22 12:47 ` [PATCH v2 0/5] x86: Switch X86_FEATURE_XENPV to cpu_feature_enabled() use Juergen Gross
5 siblings, 2 replies; 17+ messages in thread
From: Juergen Gross @ 2022-11-04 7:27 UTC (permalink / raw)
To: linux-kernel, xen-devel, x86
Cc: Juergen Gross, Dave Hansen, Andy Lutomirski, Peter Zijlstra,
Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin
Testing of X86_FEATURE_XENPV in setup_cpu_entry_area() can be removed,
as this code path is 32-bit only, and Xen PV guests are not supporting
32-bit mode.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2:
- new patch
---
arch/x86/mm/cpu_entry_area.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c
index 6c2f1b76a0b6..42cd96e7d733 100644
--- a/arch/x86/mm/cpu_entry_area.c
+++ b/arch/x86/mm/cpu_entry_area.c
@@ -138,17 +138,13 @@ static void __init setup_cpu_entry_area(unsigned int cpu)
pgprot_t tss_prot = PAGE_KERNEL_RO;
#else
/*
- * On native 32-bit systems, the GDT cannot be read-only because
+ * On 32-bit systems, the GDT cannot be read-only because
* our double fault handler uses a task gate, and entering through
* a task gate needs to change an available TSS to busy. If the
* GDT is read-only, that will triple fault. The TSS cannot be
* read-only because the CPU writes to it on task switches.
- *
- * On Xen PV, the GDT must be read-only because the hypervisor
- * requires it.
*/
- pgprot_t gdt_prot = boot_cpu_has(X86_FEATURE_XENPV) ?
- PAGE_KERNEL_RO : PAGE_KERNEL;
+ pgprot_t gdt_prot = PAGE_KERNEL;
pgprot_t tss_prot = PAGE_KERNEL;
#endif
--
2.35.3
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v2 5/5] x86: switch to cpu_feature_enabled() for X86_FEATURE_XENPV
2022-11-04 7:26 [PATCH v2 0/5] x86: Switch X86_FEATURE_XENPV to cpu_feature_enabled() use Juergen Gross
` (3 preceding siblings ...)
2022-11-04 7:27 ` [PATCH v2 4/5] x86: remove X86_FEATURE_XENPV usage in setup_cpu_entry_area() Juergen Gross
@ 2022-11-04 7:27 ` Juergen Gross
2022-11-04 17:32 ` Dave Hansen
2022-11-22 18:04 ` [tip: x86/cpu] x86/cpu: Switch " tip-bot2 for Juergen Gross
2022-11-22 12:47 ` [PATCH v2 0/5] x86: Switch X86_FEATURE_XENPV to cpu_feature_enabled() use Juergen Gross
5 siblings, 2 replies; 17+ messages in thread
From: Juergen Gross @ 2022-11-04 7:27 UTC (permalink / raw)
To: linux-kernel, xen-devel, x86
Cc: Juergen Gross, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, H. Peter Anvin, Pu Wen
Convert the remaining cases of static_cpu_has(X86_FEATURE_XENPV) and
boot_cpu_has(X86_FEATURE_XENPV) to use cpu_feature_enabled(), allowing
more efficient code in case the kernel is configured without
CONFIG_XEN_PV.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/x86/kernel/cpu/amd.c | 2 +-
arch/x86/kernel/cpu/bugs.c | 2 +-
arch/x86/kernel/cpu/hygon.c | 2 +-
arch/x86/kernel/process_64.c | 4 ++--
arch/x86/kernel/topology.c | 2 +-
5 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 860b60273df3..697fe881e967 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -985,7 +985,7 @@ static void init_amd(struct cpuinfo_x86 *c)
set_cpu_cap(c, X86_FEATURE_3DNOWPREFETCH);
/* AMD CPUs don't reset SS attributes on SYSRET, Xen does. */
- if (!cpu_has(c, X86_FEATURE_XENPV))
+ if (!cpu_feature_enabled(X86_FEATURE_XENPV))
set_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS);
/*
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index da7c361f47e0..7f78e1527c5e 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1302,7 +1302,7 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
return SPECTRE_V2_CMD_AUTO;
}
- if (cmd == SPECTRE_V2_CMD_IBRS && boot_cpu_has(X86_FEATURE_XENPV)) {
+ if (cmd == SPECTRE_V2_CMD_IBRS && cpu_feature_enabled(X86_FEATURE_XENPV)) {
pr_err("%s selected but running as XenPV guest. Switching to AUTO select\n",
mitigation_options[i].option);
return SPECTRE_V2_CMD_AUTO;
diff --git a/arch/x86/kernel/cpu/hygon.c b/arch/x86/kernel/cpu/hygon.c
index 21fd425088fe..1c27645fd429 100644
--- a/arch/x86/kernel/cpu/hygon.c
+++ b/arch/x86/kernel/cpu/hygon.c
@@ -339,7 +339,7 @@ static void init_hygon(struct cpuinfo_x86 *c)
set_cpu_cap(c, X86_FEATURE_ARAT);
/* Hygon CPUs don't reset SS attributes on SYSRET, Xen does. */
- if (!cpu_has(c, X86_FEATURE_XENPV))
+ if (!cpu_feature_enabled(X86_FEATURE_XENPV))
set_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS);
check_null_seg_clears_base(c);
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 6b3418bff326..e2f469175be8 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -165,7 +165,7 @@ static noinstr unsigned long __rdgsbase_inactive(void)
lockdep_assert_irqs_disabled();
- if (!static_cpu_has(X86_FEATURE_XENPV)) {
+ if (!cpu_feature_enabled(X86_FEATURE_XENPV)) {
native_swapgs();
gsbase = rdgsbase();
native_swapgs();
@@ -190,7 +190,7 @@ static noinstr void __wrgsbase_inactive(unsigned long gsbase)
{
lockdep_assert_irqs_disabled();
- if (!static_cpu_has(X86_FEATURE_XENPV)) {
+ if (!cpu_feature_enabled(X86_FEATURE_XENPV)) {
native_swapgs();
wrgsbase(gsbase);
native_swapgs();
diff --git a/arch/x86/kernel/topology.c b/arch/x86/kernel/topology.c
index 8617d1ed9d31..1b83377274b8 100644
--- a/arch/x86/kernel/topology.c
+++ b/arch/x86/kernel/topology.c
@@ -106,7 +106,7 @@ int arch_register_cpu(int num)
* Xen PV guests don't support CPU0 hotplug at all.
*/
if (c->x86_vendor != X86_VENDOR_INTEL ||
- boot_cpu_has(X86_FEATURE_XENPV))
+ cpu_feature_enabled(X86_FEATURE_XENPV))
cpu0_hotpluggable = 0;
/*
--
2.35.3
^ permalink raw reply related [flat|nested] 17+ messages in thread
* Re: [PATCH v2 1/5] x86: add X86_FEATURE_XENPV to disabled-features.h
2022-11-04 7:26 ` [PATCH v2 1/5] x86: add X86_FEATURE_XENPV to disabled-features.h Juergen Gross
@ 2022-11-04 14:56 ` Dave Hansen
2022-11-22 18:04 ` [tip: x86/cpu] x86/cpufeatures: Add " tip-bot2 for Juergen Gross
1 sibling, 0 replies; 17+ messages in thread
From: Dave Hansen @ 2022-11-04 14:56 UTC (permalink / raw)
To: Juergen Gross, linux-kernel, xen-devel, x86
Cc: Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen,
H. Peter Anvin
On 11/4/22 00:26, Juergen Gross wrote:
> Add X86_FEATURE_XENPV to the features handled specially in
> disabled-features.h.
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH v2 2/5] x86: remove unneeded 64-bit dependency in arch_enter_from_user_mode()
2022-11-04 7:26 ` [PATCH v2 2/5] x86: remove unneeded 64-bit dependency in arch_enter_from_user_mode() Juergen Gross
@ 2022-11-04 14:58 ` Dave Hansen
2022-11-22 18:04 ` [tip: x86/cpu] x86/cpu: Remove " tip-bot2 for Juergen Gross
1 sibling, 0 replies; 17+ messages in thread
From: Dave Hansen @ 2022-11-04 14:58 UTC (permalink / raw)
To: Juergen Gross, linux-kernel, xen-devel, x86
Cc: Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen,
H. Peter Anvin
On 11/4/22 00:26, Juergen Gross wrote:
> The check for 64-bit mode when testing X86_FEATURE_XENPV isn't needed,
> as Xen PV guests are no longer supported in 32-bit mode.
Tiniest nit if you revise this: please call out that this "no longer
supported" thing is enforced in Kconfig. It's not just some random
edict where we pronounced 32-bit PV guests unsupported.
Otherwise:
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH v2 3/5] x86: drop 32-bit Xen PV guest code in update_task_stack()
2022-11-04 7:26 ` [PATCH v2 3/5] x86: drop 32-bit Xen PV guest code in update_task_stack() Juergen Gross
@ 2022-11-04 15:04 ` Dave Hansen
2022-11-22 18:04 ` [tip: x86/cpu] x86/cpu: Drop " tip-bot2 for Juergen Gross
1 sibling, 0 replies; 17+ messages in thread
From: Dave Hansen @ 2022-11-04 15:04 UTC (permalink / raw)
To: Juergen Gross, linux-kernel, xen-devel, x86
Cc: Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen,
H. Peter Anvin
On 11/4/22 00:26, Juergen Gross wrote:
> Testing for Xen PV guest mode in a 32-bit only code section can be
> dropped, as Xen PV guests are supported in 64-bit mode only.
>
> While at it switch from boot_cpu_has() to cpu_feature_enabled() in the
> 64-bit part of the code.
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH v2 4/5] x86: remove X86_FEATURE_XENPV usage in setup_cpu_entry_area()
2022-11-04 7:27 ` [PATCH v2 4/5] x86: remove X86_FEATURE_XENPV usage in setup_cpu_entry_area() Juergen Gross
@ 2022-11-04 15:04 ` Dave Hansen
2022-11-22 18:04 ` [tip: x86/cpu] x86/cpu: Remove " tip-bot2 for Juergen Gross
1 sibling, 0 replies; 17+ messages in thread
From: Dave Hansen @ 2022-11-04 15:04 UTC (permalink / raw)
To: Juergen Gross, linux-kernel, xen-devel, x86
Cc: Dave Hansen, Andy Lutomirski, Peter Zijlstra, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, H. Peter Anvin
On 11/4/22 00:27, Juergen Gross wrote:
> Testing of X86_FEATURE_XENPV in setup_cpu_entry_area() can be removed,
> as this code path is 32-bit only, and Xen PV guests are not supporting
> 32-bit mode.
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH v2 5/5] x86: switch to cpu_feature_enabled() for X86_FEATURE_XENPV
2022-11-04 7:27 ` [PATCH v2 5/5] x86: switch to cpu_feature_enabled() for X86_FEATURE_XENPV Juergen Gross
@ 2022-11-04 17:32 ` Dave Hansen
2022-11-22 18:04 ` [tip: x86/cpu] x86/cpu: Switch " tip-bot2 for Juergen Gross
1 sibling, 0 replies; 17+ messages in thread
From: Dave Hansen @ 2022-11-04 17:32 UTC (permalink / raw)
To: Juergen Gross, linux-kernel, xen-devel, x86
Cc: Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen,
H. Peter Anvin, Pu Wen
On 11/4/22 00:27, Juergen Gross wrote:
> Convert the remaining cases of static_cpu_has(X86_FEATURE_XENPV) and
> boot_cpu_has(X86_FEATURE_XENPV) to use cpu_feature_enabled(), allowing
> more efficient code in case the kernel is configured without
> CONFIG_XEN_PV.
As with the rest:
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Seems like a very straightforward, sane set of cleanups.
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH v2 0/5] x86: Switch X86_FEATURE_XENPV to cpu_feature_enabled() use
2022-11-04 7:26 [PATCH v2 0/5] x86: Switch X86_FEATURE_XENPV to cpu_feature_enabled() use Juergen Gross
` (4 preceding siblings ...)
2022-11-04 7:27 ` [PATCH v2 5/5] x86: switch to cpu_feature_enabled() for X86_FEATURE_XENPV Juergen Gross
@ 2022-11-22 12:47 ` Juergen Gross
5 siblings, 0 replies; 17+ messages in thread
From: Juergen Gross @ 2022-11-22 12:47 UTC (permalink / raw)
To: linux-kernel, xen-devel, x86
Cc: Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen,
H. Peter Anvin, Andy Lutomirski, Peter Zijlstra, Pu Wen
[-- Attachment #1.1.1: Type: text/plain, Size: 1265 bytes --]
On 04.11.22 08:26, Juergen Gross wrote:
> Make especially kernels without CONFIG_XEN_PV more efficient by
> using cpu_feature_enabled(X86_FEATURE_XENPV) instead of boot_cpu_has()
> and friends.
>
> Changes in V2:
> - new patch 4
>
> Juergen Gross (5):
> x86: add X86_FEATURE_XENPV to disabled-features.h
> x86: remove unneeded 64-bit dependency in arch_enter_from_user_mode()
> x86: drop 32-bit Xen PV guest code in update_task_stack()
> x86: remove X86_FEATURE_XENPV usage in setup_cpu_entry_area()
> x86: switch to cpu_feature_enabled() for X86_FEATURE_XENPV
>
> arch/x86/include/asm/disabled-features.h | 8 +++++++-
> arch/x86/include/asm/entry-common.h | 4 ++--
> arch/x86/include/asm/switch_to.h | 7 ++-----
> arch/x86/kernel/cpu/amd.c | 2 +-
> arch/x86/kernel/cpu/bugs.c | 2 +-
> arch/x86/kernel/cpu/hygon.c | 2 +-
> arch/x86/kernel/process_64.c | 4 ++--
> arch/x86/kernel/topology.c | 2 +-
> arch/x86/mm/cpu_entry_area.c | 8 ++------
> 9 files changed, 19 insertions(+), 20 deletions(-)
>
The patches have all an "Ack" by Dave. I think this series should go in
via the tip tree, no?
Juergen
[-- Attachment #1.1.2: OpenPGP public key --]
[-- Type: application/pgp-keys, Size: 3149 bytes --]
[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 495 bytes --]
^ permalink raw reply [flat|nested] 17+ messages in thread
* [tip: x86/cpu] x86/cpu: Switch to cpu_feature_enabled() for X86_FEATURE_XENPV
2022-11-04 7:27 ` [PATCH v2 5/5] x86: switch to cpu_feature_enabled() for X86_FEATURE_XENPV Juergen Gross
2022-11-04 17:32 ` Dave Hansen
@ 2022-11-22 18:04 ` tip-bot2 for Juergen Gross
1 sibling, 0 replies; 17+ messages in thread
From: tip-bot2 for Juergen Gross @ 2022-11-22 18:04 UTC (permalink / raw)
To: linux-tip-commits
Cc: Juergen Gross, Borislav Petkov, Dave Hansen, x86, linux-kernel
The following commit has been merged into the x86/cpu branch of tip:
Commit-ID: 6007878a782eb96f50a71c3a06cf3e931cf8aac1
Gitweb: https://git.kernel.org/tip/6007878a782eb96f50a71c3a06cf3e931cf8aac1
Author: Juergen Gross <jgross@suse.com>
AuthorDate: Fri, 04 Nov 2022 08:27:01 +01:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Tue, 22 Nov 2022 16:18:19 +01:00
x86/cpu: Switch to cpu_feature_enabled() for X86_FEATURE_XENPV
Convert the remaining cases of static_cpu_has(X86_FEATURE_XENPV) and
boot_cpu_has(X86_FEATURE_XENPV) to use cpu_feature_enabled(), allowing
more efficient code in case the kernel is configured without
CONFIG_XEN_PV.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20221104072701.20283-6-jgross@suse.com
---
arch/x86/kernel/cpu/amd.c | 2 +-
arch/x86/kernel/cpu/bugs.c | 2 +-
arch/x86/kernel/cpu/hygon.c | 2 +-
arch/x86/kernel/process_64.c | 4 ++--
arch/x86/kernel/topology.c | 2 +-
5 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 860b602..697fe88 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -985,7 +985,7 @@ static void init_amd(struct cpuinfo_x86 *c)
set_cpu_cap(c, X86_FEATURE_3DNOWPREFETCH);
/* AMD CPUs don't reset SS attributes on SYSRET, Xen does. */
- if (!cpu_has(c, X86_FEATURE_XENPV))
+ if (!cpu_feature_enabled(X86_FEATURE_XENPV))
set_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS);
/*
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index e254f07..9e84b68 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1302,7 +1302,7 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
return SPECTRE_V2_CMD_AUTO;
}
- if (cmd == SPECTRE_V2_CMD_IBRS && boot_cpu_has(X86_FEATURE_XENPV)) {
+ if (cmd == SPECTRE_V2_CMD_IBRS && cpu_feature_enabled(X86_FEATURE_XENPV)) {
pr_err("%s selected but running as XenPV guest. Switching to AUTO select\n",
mitigation_options[i].option);
return SPECTRE_V2_CMD_AUTO;
diff --git a/arch/x86/kernel/cpu/hygon.c b/arch/x86/kernel/cpu/hygon.c
index 21fd425..1c27645 100644
--- a/arch/x86/kernel/cpu/hygon.c
+++ b/arch/x86/kernel/cpu/hygon.c
@@ -339,7 +339,7 @@ static void init_hygon(struct cpuinfo_x86 *c)
set_cpu_cap(c, X86_FEATURE_ARAT);
/* Hygon CPUs don't reset SS attributes on SYSRET, Xen does. */
- if (!cpu_has(c, X86_FEATURE_XENPV))
+ if (!cpu_feature_enabled(X86_FEATURE_XENPV))
set_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS);
check_null_seg_clears_base(c);
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 6b3418b..e2f4691 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -165,7 +165,7 @@ static noinstr unsigned long __rdgsbase_inactive(void)
lockdep_assert_irqs_disabled();
- if (!static_cpu_has(X86_FEATURE_XENPV)) {
+ if (!cpu_feature_enabled(X86_FEATURE_XENPV)) {
native_swapgs();
gsbase = rdgsbase();
native_swapgs();
@@ -190,7 +190,7 @@ static noinstr void __wrgsbase_inactive(unsigned long gsbase)
{
lockdep_assert_irqs_disabled();
- if (!static_cpu_has(X86_FEATURE_XENPV)) {
+ if (!cpu_feature_enabled(X86_FEATURE_XENPV)) {
native_swapgs();
wrgsbase(gsbase);
native_swapgs();
diff --git a/arch/x86/kernel/topology.c b/arch/x86/kernel/topology.c
index 8617d1e..1b83377 100644
--- a/arch/x86/kernel/topology.c
+++ b/arch/x86/kernel/topology.c
@@ -106,7 +106,7 @@ int arch_register_cpu(int num)
* Xen PV guests don't support CPU0 hotplug at all.
*/
if (c->x86_vendor != X86_VENDOR_INTEL ||
- boot_cpu_has(X86_FEATURE_XENPV))
+ cpu_feature_enabled(X86_FEATURE_XENPV))
cpu0_hotpluggable = 0;
/*
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [tip: x86/cpu] x86/cpu: Remove X86_FEATURE_XENPV usage in setup_cpu_entry_area()
2022-11-04 7:27 ` [PATCH v2 4/5] x86: remove X86_FEATURE_XENPV usage in setup_cpu_entry_area() Juergen Gross
2022-11-04 15:04 ` Dave Hansen
@ 2022-11-22 18:04 ` tip-bot2 for Juergen Gross
1 sibling, 0 replies; 17+ messages in thread
From: tip-bot2 for Juergen Gross @ 2022-11-22 18:04 UTC (permalink / raw)
To: linux-tip-commits
Cc: Juergen Gross, Borislav Petkov, Dave Hansen, x86, linux-kernel
The following commit has been merged into the x86/cpu branch of tip:
Commit-ID: d76c4f7a610ac56c5b06e34258859945e77d190c
Gitweb: https://git.kernel.org/tip/d76c4f7a610ac56c5b06e34258859945e77d190c
Author: Juergen Gross <jgross@suse.com>
AuthorDate: Fri, 04 Nov 2022 08:27:00 +01:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Tue, 22 Nov 2022 16:16:25 +01:00
x86/cpu: Remove X86_FEATURE_XENPV usage in setup_cpu_entry_area()
Testing of X86_FEATURE_XENPV in setup_cpu_entry_area() can be removed,
as this code path is 32-bit only, and Xen PV guests are 64-bit only.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20221104072701.20283-5-jgross@suse.com
---
arch/x86/mm/cpu_entry_area.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c
index 6c2f1b7..42cd96e 100644
--- a/arch/x86/mm/cpu_entry_area.c
+++ b/arch/x86/mm/cpu_entry_area.c
@@ -138,17 +138,13 @@ static void __init setup_cpu_entry_area(unsigned int cpu)
pgprot_t tss_prot = PAGE_KERNEL_RO;
#else
/*
- * On native 32-bit systems, the GDT cannot be read-only because
+ * On 32-bit systems, the GDT cannot be read-only because
* our double fault handler uses a task gate, and entering through
* a task gate needs to change an available TSS to busy. If the
* GDT is read-only, that will triple fault. The TSS cannot be
* read-only because the CPU writes to it on task switches.
- *
- * On Xen PV, the GDT must be read-only because the hypervisor
- * requires it.
*/
- pgprot_t gdt_prot = boot_cpu_has(X86_FEATURE_XENPV) ?
- PAGE_KERNEL_RO : PAGE_KERNEL;
+ pgprot_t gdt_prot = PAGE_KERNEL;
pgprot_t tss_prot = PAGE_KERNEL;
#endif
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [tip: x86/cpu] x86/cpu: Drop 32-bit Xen PV guest code in update_task_stack()
2022-11-04 7:26 ` [PATCH v2 3/5] x86: drop 32-bit Xen PV guest code in update_task_stack() Juergen Gross
2022-11-04 15:04 ` Dave Hansen
@ 2022-11-22 18:04 ` tip-bot2 for Juergen Gross
1 sibling, 0 replies; 17+ messages in thread
From: tip-bot2 for Juergen Gross @ 2022-11-22 18:04 UTC (permalink / raw)
To: linux-tip-commits
Cc: Juergen Gross, Borislav Petkov, Dave Hansen, x86, linux-kernel
The following commit has been merged into the x86/cpu branch of tip:
Commit-ID: dfbd9e4059c4edad4d92ef7f3deb4954f76e4ba0
Gitweb: https://git.kernel.org/tip/dfbd9e4059c4edad4d92ef7f3deb4954f76e4ba0
Author: Juergen Gross <jgross@suse.com>
AuthorDate: Fri, 04 Nov 2022 08:26:59 +01:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Tue, 22 Nov 2022 16:14:15 +01:00
x86/cpu: Drop 32-bit Xen PV guest code in update_task_stack()
Testing for Xen PV guest mode in a 32-bit only code section can be
dropped, as Xen PV guests are supported in 64-bit mode only.
While at it, switch from boot_cpu_has() to cpu_feature_enabled() in the
64-bit part of the code.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20221104072701.20283-4-jgross@suse.com
---
arch/x86/include/asm/switch_to.h | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h
index c08eb0f..5c91305 100644
--- a/arch/x86/include/asm/switch_to.h
+++ b/arch/x86/include/asm/switch_to.h
@@ -66,13 +66,10 @@ static inline void update_task_stack(struct task_struct *task)
{
/* sp0 always points to the entry trampoline stack, which is constant: */
#ifdef CONFIG_X86_32
- if (static_cpu_has(X86_FEATURE_XENPV))
- load_sp0(task->thread.sp0);
- else
- this_cpu_write(cpu_tss_rw.x86_tss.sp1, task->thread.sp0);
+ this_cpu_write(cpu_tss_rw.x86_tss.sp1, task->thread.sp0);
#else
/* Xen PV enters the kernel on the thread stack. */
- if (static_cpu_has(X86_FEATURE_XENPV))
+ if (cpu_feature_enabled(X86_FEATURE_XENPV))
load_sp0(task_top_of_stack(task));
#endif
}
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [tip: x86/cpu] x86/cpu: Remove unneeded 64-bit dependency in arch_enter_from_user_mode()
2022-11-04 7:26 ` [PATCH v2 2/5] x86: remove unneeded 64-bit dependency in arch_enter_from_user_mode() Juergen Gross
2022-11-04 14:58 ` Dave Hansen
@ 2022-11-22 18:04 ` tip-bot2 for Juergen Gross
1 sibling, 0 replies; 17+ messages in thread
From: tip-bot2 for Juergen Gross @ 2022-11-22 18:04 UTC (permalink / raw)
To: linux-tip-commits
Cc: Juergen Gross, Borislav Petkov, Dave Hansen, x86, linux-kernel
The following commit has been merged into the x86/cpu branch of tip:
Commit-ID: 0bafc51babe2344e9b0ff6629a4f044727728349
Gitweb: https://git.kernel.org/tip/0bafc51babe2344e9b0ff6629a4f044727728349
Author: Juergen Gross <jgross@suse.com>
AuthorDate: Fri, 04 Nov 2022 08:26:58 +01:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Tue, 22 Nov 2022 16:11:57 +01:00
x86/cpu: Remove unneeded 64-bit dependency in arch_enter_from_user_mode()
The check for 64-bit mode when testing X86_FEATURE_XENPV isn't needed,
as Xen PV guests are no longer supported in 32-bit mode, see
a13f2ef168cb ("x86/xen: remove 32-bit Xen PV guest support").
While at it switch from boot_cpu_has() to cpu_feature_enabled().
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20221104072701.20283-3-jgross@suse.com
---
arch/x86/include/asm/entry-common.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/entry-common.h b/arch/x86/include/asm/entry-common.h
index 674ed46..1179038 100644
--- a/arch/x86/include/asm/entry-common.h
+++ b/arch/x86/include/asm/entry-common.h
@@ -24,8 +24,8 @@ static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs)
/*
* For !SMAP hardware we patch out CLAC on entry.
*/
- if (boot_cpu_has(X86_FEATURE_SMAP) ||
- (IS_ENABLED(CONFIG_64BIT) && boot_cpu_has(X86_FEATURE_XENPV)))
+ if (cpu_feature_enabled(X86_FEATURE_SMAP) ||
+ cpu_feature_enabled(X86_FEATURE_XENPV))
mask |= X86_EFLAGS_AC;
WARN_ON_ONCE(flags & mask);
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [tip: x86/cpu] x86/cpufeatures: Add X86_FEATURE_XENPV to disabled-features.h
2022-11-04 7:26 ` [PATCH v2 1/5] x86: add X86_FEATURE_XENPV to disabled-features.h Juergen Gross
2022-11-04 14:56 ` Dave Hansen
@ 2022-11-22 18:04 ` tip-bot2 for Juergen Gross
1 sibling, 0 replies; 17+ messages in thread
From: tip-bot2 for Juergen Gross @ 2022-11-22 18:04 UTC (permalink / raw)
To: linux-tip-commits
Cc: Juergen Gross, Borislav Petkov, Dave Hansen, x86, linux-kernel
The following commit has been merged into the x86/cpu branch of tip:
Commit-ID: 15e15d64bd8e12d835f6bb1b1ce3ffa13fa03a66
Gitweb: https://git.kernel.org/tip/15e15d64bd8e12d835f6bb1b1ce3ffa13fa03a66
Author: Juergen Gross <jgross@suse.com>
AuthorDate: Fri, 04 Nov 2022 08:26:57 +01:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Tue, 22 Nov 2022 15:42:33 +01:00
x86/cpufeatures: Add X86_FEATURE_XENPV to disabled-features.h
Add X86_FEATURE_XENPV to the features handled specially in
disabled-features.h.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20221104072701.20283-2-jgross@suse.com
---
arch/x86/include/asm/disabled-features.h | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index 33d2cd0..c862552 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -81,6 +81,12 @@
# define DISABLE_SGX (1 << (X86_FEATURE_SGX & 31))
#endif
+#ifdef CONFIG_XEN_PV
+# define DISABLE_XENPV 0
+#else
+# define DISABLE_XENPV (1 << (X86_FEATURE_XENPV & 31))
+#endif
+
#ifdef CONFIG_INTEL_TDX_GUEST
# define DISABLE_TDX_GUEST 0
#else
@@ -98,7 +104,7 @@
#define DISABLED_MASK5 0
#define DISABLED_MASK6 0
#define DISABLED_MASK7 (DISABLE_PTI)
-#define DISABLED_MASK8 (DISABLE_TDX_GUEST)
+#define DISABLED_MASK8 (DISABLE_XENPV|DISABLE_TDX_GUEST)
#define DISABLED_MASK9 (DISABLE_SGX)
#define DISABLED_MASK10 0
#define DISABLED_MASK11 (DISABLE_RETPOLINE|DISABLE_RETHUNK|DISABLE_UNRET)
^ permalink raw reply related [flat|nested] 17+ messages in thread
end of thread, other threads:[~2022-11-22 18:05 UTC | newest]
Thread overview: 17+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-11-04 7:26 [PATCH v2 0/5] x86: Switch X86_FEATURE_XENPV to cpu_feature_enabled() use Juergen Gross
2022-11-04 7:26 ` [PATCH v2 1/5] x86: add X86_FEATURE_XENPV to disabled-features.h Juergen Gross
2022-11-04 14:56 ` Dave Hansen
2022-11-22 18:04 ` [tip: x86/cpu] x86/cpufeatures: Add " tip-bot2 for Juergen Gross
2022-11-04 7:26 ` [PATCH v2 2/5] x86: remove unneeded 64-bit dependency in arch_enter_from_user_mode() Juergen Gross
2022-11-04 14:58 ` Dave Hansen
2022-11-22 18:04 ` [tip: x86/cpu] x86/cpu: Remove " tip-bot2 for Juergen Gross
2022-11-04 7:26 ` [PATCH v2 3/5] x86: drop 32-bit Xen PV guest code in update_task_stack() Juergen Gross
2022-11-04 15:04 ` Dave Hansen
2022-11-22 18:04 ` [tip: x86/cpu] x86/cpu: Drop " tip-bot2 for Juergen Gross
2022-11-04 7:27 ` [PATCH v2 4/5] x86: remove X86_FEATURE_XENPV usage in setup_cpu_entry_area() Juergen Gross
2022-11-04 15:04 ` Dave Hansen
2022-11-22 18:04 ` [tip: x86/cpu] x86/cpu: Remove " tip-bot2 for Juergen Gross
2022-11-04 7:27 ` [PATCH v2 5/5] x86: switch to cpu_feature_enabled() for X86_FEATURE_XENPV Juergen Gross
2022-11-04 17:32 ` Dave Hansen
2022-11-22 18:04 ` [tip: x86/cpu] x86/cpu: Switch " tip-bot2 for Juergen Gross
2022-11-22 12:47 ` [PATCH v2 0/5] x86: Switch X86_FEATURE_XENPV to cpu_feature_enabled() use Juergen Gross
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