* [PATCH v4 04/15] x86/pv: switch SWAPGS to ALTERNATIVE
2021-01-20 13:25 [PATCH v4 00/15] x86: major paravirt cleanup Juergen Gross via Virtualization
@ 2021-01-20 13:26 ` Juergen Gross via Virtualization
2021-01-20 13:26 ` [PATCH v4 05/15] x86/xen: drop USERGS_SYSRET64 paravirt call Juergen Gross via Virtualization
` (9 subsequent siblings)
10 siblings, 0 replies; 15+ messages in thread
From: Juergen Gross via Virtualization @ 2021-01-20 13:26 UTC (permalink / raw)
To: bpetkov, x86, linux-kernel, virtualization
SWAPGS is used only for interrupts coming from user mode or for
returning to user mode. So there is no reason to use the PARAVIRT
framework, as it can easily be replaced by an ALTERNATIVE depending
on X86_FEATURE_XENPV.
There are several instances using the PV-aware SWAPGS macro in paths
which are never executed in a Xen PV guest. Replace those with the
plain swapgs instruction. For SWAPGS_UNSAFE_STACK the same applies.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/entry/entry_64.S | 10 +++++-----
arch/x86/include/asm/irqflags.h | 20 ++++++++------------
arch/x86/include/asm/paravirt.h | 20 --------------------
arch/x86/include/asm/paravirt_types.h | 2 --
arch/x86/kernel/asm-offsets_64.c | 1 -
arch/x86/kernel/paravirt.c | 1 -
arch/x86/kernel/paravirt_patch.c | 3 ---
arch/x86/xen/enlighten_pv.c | 3 ---
8 files changed, 13 insertions(+), 47 deletions(-)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index cad08703c4ad..a876204a73e0 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -669,7 +669,7 @@ native_irq_return_ldt:
*/
pushq %rdi /* Stash user RDI */
- SWAPGS /* to kernel GS */
+ swapgs /* to kernel GS */
SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi /* to kernel CR3 */
movq PER_CPU_VAR(espfix_waddr), %rdi
@@ -699,7 +699,7 @@ native_irq_return_ldt:
orq PER_CPU_VAR(espfix_stack), %rax
SWITCH_TO_USER_CR3_STACK scratch_reg=%rdi
- SWAPGS /* to user GS */
+ swapgs /* to user GS */
popq %rdi /* Restore user RDI */
movq %rax, %rsp
@@ -943,7 +943,7 @@ SYM_CODE_START_LOCAL(paranoid_entry)
ret
.Lparanoid_entry_swapgs:
- SWAPGS
+ swapgs
/*
* The above SAVE_AND_SWITCH_TO_KERNEL_CR3 macro doesn't do an
@@ -1001,7 +1001,7 @@ SYM_CODE_START_LOCAL(paranoid_exit)
jnz restore_regs_and_return_to_kernel
/* We are returning to a context with user GSBASE */
- SWAPGS_UNSAFE_STACK
+ swapgs
jmp restore_regs_and_return_to_kernel
SYM_CODE_END(paranoid_exit)
@@ -1426,7 +1426,7 @@ nmi_no_fsgsbase:
jnz nmi_restore
nmi_swapgs:
- SWAPGS_UNSAFE_STACK
+ swapgs
nmi_restore:
POP_REGS
diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index 2dfc8d380dab..8c86edefa115 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -131,18 +131,6 @@ static __always_inline unsigned long arch_local_irq_save(void)
#define SAVE_FLAGS(x) pushfq; popq %rax
#endif
-#define SWAPGS swapgs
-/*
- * Currently paravirt can't handle swapgs nicely when we
- * don't have a stack we can rely on (such as a user space
- * stack). So we either find a way around these or just fault
- * and emulate if a guest tries to call swapgs directly.
- *
- * Either way, this is a good way to document that we don't
- * have a reliable stack. x86_64 only.
- */
-#define SWAPGS_UNSAFE_STACK swapgs
-
#define INTERRUPT_RETURN jmp native_iret
#define USERGS_SYSRET64 \
swapgs; \
@@ -170,6 +158,14 @@ static __always_inline int arch_irqs_disabled(void)
return arch_irqs_disabled_flags(flags);
}
+#else
+#ifdef CONFIG_X86_64
+#ifdef CONFIG_XEN_PV
+#define SWAPGS ALTERNATIVE "swapgs", "", X86_FEATURE_XENPV
+#else
+#define SWAPGS swapgs
+#endif
+#endif
#endif /* !__ASSEMBLY__ */
#endif
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index f8dce11d2bc1..f2ebe109a37e 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -776,26 +776,6 @@ extern void default_banner(void);
#ifdef CONFIG_X86_64
#ifdef CONFIG_PARAVIRT_XXL
-/*
- * If swapgs is used while the userspace stack is still current,
- * there's no way to call a pvop. The PV replacement *must* be
- * inlined, or the swapgs instruction must be trapped and emulated.
- */
-#define SWAPGS_UNSAFE_STACK \
- PARA_SITE(PARA_PATCH(PV_CPU_swapgs), swapgs)
-
-/*
- * Note: swapgs is very special, and in practise is either going to be
- * implemented with a single "swapgs" instruction or something very
- * special. Either way, we don't need to save any registers for
- * it.
- */
-#define SWAPGS \
- PARA_SITE(PARA_PATCH(PV_CPU_swapgs), \
- ANNOTATE_RETPOLINE_SAFE; \
- call PARA_INDIRECT(pv_ops+PV_CPU_swapgs); \
- )
-
#define USERGS_SYSRET64 \
PARA_SITE(PARA_PATCH(PV_CPU_usergs_sysret64), \
ANNOTATE_RETPOLINE_SAFE; \
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index b6b02b7c19cc..130f428b0cc8 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -168,8 +168,6 @@ struct pv_cpu_ops {
frame set up. */
void (*iret)(void);
- void (*swapgs)(void);
-
void (*start_context_switch)(struct task_struct *prev);
void (*end_context_switch)(struct task_struct *next);
#endif
diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index 828be792231e..1354bc30614d 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -15,7 +15,6 @@ int main(void)
#ifdef CONFIG_PARAVIRT_XXL
OFFSET(PV_CPU_usergs_sysret64, paravirt_patch_template,
cpu.usergs_sysret64);
- OFFSET(PV_CPU_swapgs, paravirt_patch_template, cpu.swapgs);
#ifdef CONFIG_DEBUG_ENTRY
OFFSET(PV_IRQ_save_fl, paravirt_patch_template, irq.save_fl);
#endif
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 6c3407ba6ee9..5e5fcf5c376d 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -312,7 +312,6 @@ struct paravirt_patch_template pv_ops = {
.cpu.usergs_sysret64 = native_usergs_sysret64,
.cpu.iret = native_iret,
- .cpu.swapgs = native_swapgs,
#ifdef CONFIG_X86_IOPL_IOPERM
.cpu.invalidate_io_bitmap = native_tss_invalidate_io_bitmap,
diff --git a/arch/x86/kernel/paravirt_patch.c b/arch/x86/kernel/paravirt_patch.c
index ace6e334cb39..7c518b08aa3c 100644
--- a/arch/x86/kernel/paravirt_patch.c
+++ b/arch/x86/kernel/paravirt_patch.c
@@ -28,7 +28,6 @@ struct patch_xxl {
const unsigned char irq_restore_fl[2];
const unsigned char cpu_wbinvd[2];
const unsigned char cpu_usergs_sysret64[6];
- const unsigned char cpu_swapgs[3];
const unsigned char mov64[3];
};
@@ -43,7 +42,6 @@ static const struct patch_xxl patch_data_xxl = {
.cpu_wbinvd = { 0x0f, 0x09 }, // wbinvd
.cpu_usergs_sysret64 = { 0x0f, 0x01, 0xf8,
0x48, 0x0f, 0x07 }, // swapgs; sysretq
- .cpu_swapgs = { 0x0f, 0x01, 0xf8 }, // swapgs
.mov64 = { 0x48, 0x89, 0xf8 }, // mov %rdi, %rax
};
@@ -86,7 +84,6 @@ unsigned int native_patch(u8 type, void *insn_buff, unsigned long addr,
PATCH_CASE(mmu, write_cr3, xxl, insn_buff, len);
PATCH_CASE(cpu, usergs_sysret64, xxl, insn_buff, len);
- PATCH_CASE(cpu, swapgs, xxl, insn_buff, len);
PATCH_CASE(cpu, wbinvd, xxl, insn_buff, len);
#endif
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 76616024129e..44bb18adfb51 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -1085,9 +1085,6 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = {
#endif
.io_delay = xen_io_delay,
- /* Xen takes care of %gs when switching to usermode for us */
- .swapgs = paravirt_nop,
-
.start_context_switch = paravirt_start_context_switch,
.end_context_switch = xen_end_context_switch,
};
--
2.26.2
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^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v4 05/15] x86/xen: drop USERGS_SYSRET64 paravirt call
2021-01-20 13:25 [PATCH v4 00/15] x86: major paravirt cleanup Juergen Gross via Virtualization
2021-01-20 13:26 ` [PATCH v4 04/15] x86/pv: switch SWAPGS to ALTERNATIVE Juergen Gross via Virtualization
@ 2021-01-20 13:26 ` Juergen Gross via Virtualization
2021-01-20 13:26 ` [PATCH v4 06/15] x86: rework arch_local_irq_restore() to not use popf Juergen Gross via Virtualization
` (8 subsequent siblings)
10 siblings, 0 replies; 15+ messages in thread
From: Juergen Gross via Virtualization @ 2021-01-20 13:26 UTC (permalink / raw)
To: bpetkov, x86, linux-kernel, virtualization
USERGS_SYSRET64 is used to return from a syscall via sysret, but
a Xen PV guest will nevertheless use the iret hypercall, as there
is no sysret PV hypercall defined.
So instead of testing all the prerequisites for doing a sysret and
then mangling the stack for Xen PV again for doing an iret just use
the iret exit from the beginning.
This can easily be done via an ALTERNATIVE like it is done for the
sysenter compat case already.
It should be noted that this drops the optimization in Xen for not
restoring a few registers when returning to user mode, but it seems
as if the saved instructions in the kernel more than compensate for
this drop (a kernel build in a Xen PV guest was slightly faster with
this patch applied).
While at it remove the stale sysret32 remnants.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V3:
- simplify ALTERNATIVE (Boris Petkov)
---
arch/x86/entry/entry_64.S | 16 +++++++---------
arch/x86/include/asm/irqflags.h | 6 ------
arch/x86/include/asm/paravirt.h | 5 -----
arch/x86/include/asm/paravirt_types.h | 8 --------
arch/x86/kernel/asm-offsets_64.c | 2 --
arch/x86/kernel/paravirt.c | 5 +----
arch/x86/kernel/paravirt_patch.c | 4 ----
arch/x86/xen/enlighten_pv.c | 1 -
arch/x86/xen/xen-asm.S | 20 --------------------
arch/x86/xen/xen-ops.h | 2 --
10 files changed, 8 insertions(+), 61 deletions(-)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index a876204a73e0..ce0464d630a2 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -46,14 +46,6 @@
.code64
.section .entry.text, "ax"
-#ifdef CONFIG_PARAVIRT_XXL
-SYM_CODE_START(native_usergs_sysret64)
- UNWIND_HINT_EMPTY
- swapgs
- sysretq
-SYM_CODE_END(native_usergs_sysret64)
-#endif /* CONFIG_PARAVIRT_XXL */
-
/*
* 64-bit SYSCALL instruction entry. Up to 6 arguments in registers.
*
@@ -123,7 +115,12 @@ SYM_INNER_LABEL(entry_SYSCALL_64_after_hwframe, SYM_L_GLOBAL)
* Try to use SYSRET instead of IRET if we're returning to
* a completely clean 64-bit userspace context. If we're not,
* go to the slow exit path.
+ * In the Xen PV case we must use iret anyway.
*/
+
+ ALTERNATIVE "", "jmp swapgs_restore_regs_and_return_to_usermode", \
+ X86_FEATURE_XENPV
+
movq RCX(%rsp), %rcx
movq RIP(%rsp), %r11
@@ -215,7 +212,8 @@ syscall_return_via_sysret:
popq %rdi
popq %rsp
- USERGS_SYSRET64
+ swapgs
+ sysretq
SYM_CODE_END(entry_SYSCALL_64)
/*
diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index 8c86edefa115..e585a4705b8d 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -132,12 +132,6 @@ static __always_inline unsigned long arch_local_irq_save(void)
#endif
#define INTERRUPT_RETURN jmp native_iret
-#define USERGS_SYSRET64 \
- swapgs; \
- sysretq;
-#define USERGS_SYSRET32 \
- swapgs; \
- sysretl
#else
#define INTERRUPT_RETURN iret
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index f2ebe109a37e..dd43b1100a87 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -776,11 +776,6 @@ extern void default_banner(void);
#ifdef CONFIG_X86_64
#ifdef CONFIG_PARAVIRT_XXL
-#define USERGS_SYSRET64 \
- PARA_SITE(PARA_PATCH(PV_CPU_usergs_sysret64), \
- ANNOTATE_RETPOLINE_SAFE; \
- jmp PARA_INDIRECT(pv_ops+PV_CPU_usergs_sysret64);)
-
#ifdef CONFIG_DEBUG_ENTRY
#define SAVE_FLAGS(clobbers) \
PARA_SITE(PARA_PATCH(PV_IRQ_save_fl), \
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 130f428b0cc8..0169365f1403 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -156,14 +156,6 @@ struct pv_cpu_ops {
u64 (*read_pmc)(int counter);
- /*
- * Switch to usermode gs and return to 64-bit usermode using
- * sysret. Only used in 64-bit kernels to return to 64-bit
- * processes. Usermode register state, including %rsp, must
- * already be restored.
- */
- void (*usergs_sysret64)(void);
-
/* Normal iret. Jump to this with the standard iret stack
frame set up. */
void (*iret)(void);
diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index 1354bc30614d..b14533af7676 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -13,8 +13,6 @@ int main(void)
{
#ifdef CONFIG_PARAVIRT
#ifdef CONFIG_PARAVIRT_XXL
- OFFSET(PV_CPU_usergs_sysret64, paravirt_patch_template,
- cpu.usergs_sysret64);
#ifdef CONFIG_DEBUG_ENTRY
OFFSET(PV_IRQ_save_fl, paravirt_patch_template, irq.save_fl);
#endif
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 5e5fcf5c376d..18560b71e717 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -135,8 +135,7 @@ unsigned paravirt_patch_default(u8 type, void *insn_buff,
else if (opfunc == _paravirt_ident_64)
ret = paravirt_patch_ident_64(insn_buff, len);
- else if (type == PARAVIRT_PATCH(cpu.iret) ||
- type == PARAVIRT_PATCH(cpu.usergs_sysret64))
+ else if (type == PARAVIRT_PATCH(cpu.iret))
/* If operation requires a jmp, then jmp */
ret = paravirt_patch_jmp(insn_buff, opfunc, addr, len);
#endif
@@ -170,7 +169,6 @@ static u64 native_steal_clock(int cpu)
/* These are in entry.S */
extern void native_iret(void);
-extern void native_usergs_sysret64(void);
static struct resource reserve_ioports = {
.start = 0,
@@ -310,7 +308,6 @@ struct paravirt_patch_template pv_ops = {
.cpu.load_sp0 = native_load_sp0,
- .cpu.usergs_sysret64 = native_usergs_sysret64,
.cpu.iret = native_iret,
#ifdef CONFIG_X86_IOPL_IOPERM
diff --git a/arch/x86/kernel/paravirt_patch.c b/arch/x86/kernel/paravirt_patch.c
index 7c518b08aa3c..2fada2c347c9 100644
--- a/arch/x86/kernel/paravirt_patch.c
+++ b/arch/x86/kernel/paravirt_patch.c
@@ -27,7 +27,6 @@ struct patch_xxl {
const unsigned char mmu_write_cr3[3];
const unsigned char irq_restore_fl[2];
const unsigned char cpu_wbinvd[2];
- const unsigned char cpu_usergs_sysret64[6];
const unsigned char mov64[3];
};
@@ -40,8 +39,6 @@ static const struct patch_xxl patch_data_xxl = {
.mmu_write_cr3 = { 0x0f, 0x22, 0xdf }, // mov %rdi, %cr3
.irq_restore_fl = { 0x57, 0x9d }, // push %rdi; popfq
.cpu_wbinvd = { 0x0f, 0x09 }, // wbinvd
- .cpu_usergs_sysret64 = { 0x0f, 0x01, 0xf8,
- 0x48, 0x0f, 0x07 }, // swapgs; sysretq
.mov64 = { 0x48, 0x89, 0xf8 }, // mov %rdi, %rax
};
@@ -83,7 +80,6 @@ unsigned int native_patch(u8 type, void *insn_buff, unsigned long addr,
PATCH_CASE(mmu, read_cr3, xxl, insn_buff, len);
PATCH_CASE(mmu, write_cr3, xxl, insn_buff, len);
- PATCH_CASE(cpu, usergs_sysret64, xxl, insn_buff, len);
PATCH_CASE(cpu, wbinvd, xxl, insn_buff, len);
#endif
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 44bb18adfb51..5476423fc6d0 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -1060,7 +1060,6 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = {
.read_pmc = xen_read_pmc,
.iret = xen_iret,
- .usergs_sysret64 = xen_sysret64,
.load_tr_desc = paravirt_nop,
.set_ldt = xen_set_ldt,
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
index 1d054c915046..c0630fd9f44e 100644
--- a/arch/x86/xen/xen-asm.S
+++ b/arch/x86/xen/xen-asm.S
@@ -214,26 +214,6 @@ SYM_CODE_START(xen_iret)
jmp hypercall_iret
SYM_CODE_END(xen_iret)
-SYM_CODE_START(xen_sysret64)
- /*
- * We're already on the usermode stack at this point, but
- * still with the kernel gs, so we can easily switch back.
- *
- * tss.sp2 is scratch space.
- */
- movq %rsp, PER_CPU_VAR(cpu_tss_rw + TSS_sp2)
- movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
-
- pushq $__USER_DS
- pushq PER_CPU_VAR(cpu_tss_rw + TSS_sp2)
- pushq %r11
- pushq $__USER_CS
- pushq %rcx
-
- pushq $VGCF_in_syscall
- jmp hypercall_iret
-SYM_CODE_END(xen_sysret64)
-
/*
* Xen handles syscall callbacks much like ordinary exceptions, which
* means we have:
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index 9546c3384c75..b2fd80a01a36 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -138,8 +138,6 @@ __visible unsigned long xen_read_cr2_direct(void);
/* These are not functions, and cannot be called normally */
__visible void xen_iret(void);
-__visible void xen_sysret32(void);
-__visible void xen_sysret64(void);
extern int xen_panic_handler_init(void);
--
2.26.2
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^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v4 06/15] x86: rework arch_local_irq_restore() to not use popf
2021-01-20 13:25 [PATCH v4 00/15] x86: major paravirt cleanup Juergen Gross via Virtualization
2021-01-20 13:26 ` [PATCH v4 04/15] x86/pv: switch SWAPGS to ALTERNATIVE Juergen Gross via Virtualization
2021-01-20 13:26 ` [PATCH v4 05/15] x86/xen: drop USERGS_SYSRET64 paravirt call Juergen Gross via Virtualization
@ 2021-01-20 13:26 ` Juergen Gross via Virtualization
2021-01-20 13:26 ` [PATCH v4 07/15] x86/paravirt: switch time pvops functions to use static_call() Juergen Gross via Virtualization
` (7 subsequent siblings)
10 siblings, 0 replies; 15+ messages in thread
From: Juergen Gross via Virtualization @ 2021-01-20 13:26 UTC (permalink / raw)
To: bpetkov, x86, linux-kernel, virtualization
"popf" is a rather expensive operation, so don't use it for restoring
irq flags. Instead test whether interrupts are enabled in the flags
parameter and enable interrupts via "sti" in that case.
This results in the restore_fl paravirt op to be no longer needed.
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/x86/include/asm/irqflags.h | 20 ++++++-------------
arch/x86/include/asm/paravirt.h | 5 -----
arch/x86/include/asm/paravirt_types.h | 7 ++-----
arch/x86/kernel/irqflags.S | 11 -----------
arch/x86/kernel/paravirt.c | 1 -
arch/x86/kernel/paravirt_patch.c | 3 ---
arch/x86/xen/enlighten_pv.c | 2 --
arch/x86/xen/irq.c | 23 ----------------------
arch/x86/xen/xen-asm.S | 28 ---------------------------
arch/x86/xen/xen-ops.h | 1 -
10 files changed, 8 insertions(+), 93 deletions(-)
diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index e585a4705b8d..144d70ea4393 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -35,15 +35,6 @@ extern __always_inline unsigned long native_save_fl(void)
return flags;
}
-extern inline void native_restore_fl(unsigned long flags);
-extern inline void native_restore_fl(unsigned long flags)
-{
- asm volatile("push %0 ; popf"
- : /* no output */
- :"g" (flags)
- :"memory", "cc");
-}
-
static __always_inline void native_irq_disable(void)
{
asm volatile("cli": : :"memory");
@@ -79,11 +70,6 @@ static __always_inline unsigned long arch_local_save_flags(void)
return native_save_fl();
}
-static __always_inline void arch_local_irq_restore(unsigned long flags)
-{
- native_restore_fl(flags);
-}
-
static __always_inline void arch_local_irq_disable(void)
{
native_irq_disable();
@@ -152,6 +138,12 @@ static __always_inline int arch_irqs_disabled(void)
return arch_irqs_disabled_flags(flags);
}
+
+static __always_inline void arch_local_irq_restore(unsigned long flags)
+{
+ if (!arch_irqs_disabled_flags(flags))
+ arch_local_irq_enable();
+}
#else
#ifdef CONFIG_X86_64
#ifdef CONFIG_XEN_PV
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index dd43b1100a87..4abf110e2243 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -648,11 +648,6 @@ static inline notrace unsigned long arch_local_save_flags(void)
return PVOP_CALLEE0(unsigned long, irq.save_fl);
}
-static inline notrace void arch_local_irq_restore(unsigned long f)
-{
- PVOP_VCALLEE1(irq.restore_fl, f);
-}
-
static inline notrace void arch_local_irq_disable(void)
{
PVOP_VCALLEE0(irq.irq_disable);
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 0169365f1403..de87087d3bde 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -168,16 +168,13 @@ struct pv_cpu_ops {
struct pv_irq_ops {
#ifdef CONFIG_PARAVIRT_XXL
/*
- * Get/set interrupt state. save_fl and restore_fl are only
- * expected to use X86_EFLAGS_IF; all other bits
- * returned from save_fl are undefined, and may be ignored by
- * restore_fl.
+ * Get/set interrupt state. save_fl is expected to use X86_EFLAGS_IF;
+ * all other bits returned from save_fl are undefined.
*
* NOTE: These functions callers expect the callee to preserve
* more registers than the standard C calling convention.
*/
struct paravirt_callee_save save_fl;
- struct paravirt_callee_save restore_fl;
struct paravirt_callee_save irq_disable;
struct paravirt_callee_save irq_enable;
diff --git a/arch/x86/kernel/irqflags.S b/arch/x86/kernel/irqflags.S
index 0db0375235b4..8ef35063964b 100644
--- a/arch/x86/kernel/irqflags.S
+++ b/arch/x86/kernel/irqflags.S
@@ -13,14 +13,3 @@ SYM_FUNC_START(native_save_fl)
ret
SYM_FUNC_END(native_save_fl)
EXPORT_SYMBOL(native_save_fl)
-
-/*
- * void native_restore_fl(unsigned long flags)
- * %eax/%rdi: flags
- */
-SYM_FUNC_START(native_restore_fl)
- push %_ASM_ARG1
- popf
- ret
-SYM_FUNC_END(native_restore_fl)
-EXPORT_SYMBOL(native_restore_fl)
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 18560b71e717..c60222ab8ab9 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -320,7 +320,6 @@ struct paravirt_patch_template pv_ops = {
/* Irq ops. */
.irq.save_fl = __PV_IS_CALLEE_SAVE(native_save_fl),
- .irq.restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl),
.irq.irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable),
.irq.irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
.irq.safe_halt = native_safe_halt,
diff --git a/arch/x86/kernel/paravirt_patch.c b/arch/x86/kernel/paravirt_patch.c
index 2fada2c347c9..abd27ec67397 100644
--- a/arch/x86/kernel/paravirt_patch.c
+++ b/arch/x86/kernel/paravirt_patch.c
@@ -25,7 +25,6 @@ struct patch_xxl {
const unsigned char mmu_read_cr2[3];
const unsigned char mmu_read_cr3[3];
const unsigned char mmu_write_cr3[3];
- const unsigned char irq_restore_fl[2];
const unsigned char cpu_wbinvd[2];
const unsigned char mov64[3];
};
@@ -37,7 +36,6 @@ static const struct patch_xxl patch_data_xxl = {
.mmu_read_cr2 = { 0x0f, 0x20, 0xd0 }, // mov %cr2, %[re]ax
.mmu_read_cr3 = { 0x0f, 0x20, 0xd8 }, // mov %cr3, %[re]ax
.mmu_write_cr3 = { 0x0f, 0x22, 0xdf }, // mov %rdi, %cr3
- .irq_restore_fl = { 0x57, 0x9d }, // push %rdi; popfq
.cpu_wbinvd = { 0x0f, 0x09 }, // wbinvd
.mov64 = { 0x48, 0x89, 0xf8 }, // mov %rdi, %rax
};
@@ -71,7 +69,6 @@ unsigned int native_patch(u8 type, void *insn_buff, unsigned long addr,
switch (type) {
#ifdef CONFIG_PARAVIRT_XXL
- PATCH_CASE(irq, restore_fl, xxl, insn_buff, len);
PATCH_CASE(irq, save_fl, xxl, insn_buff, len);
PATCH_CASE(irq, irq_enable, xxl, insn_buff, len);
PATCH_CASE(irq, irq_disable, xxl, insn_buff, len);
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 5476423fc6d0..32b295cc2716 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -1022,8 +1022,6 @@ void __init xen_setup_vcpu_info_placement(void)
*/
if (xen_have_vcpu_info_placement) {
pv_ops.irq.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct);
- pv_ops.irq.restore_fl =
- __PV_IS_CALLEE_SAVE(xen_restore_fl_direct);
pv_ops.irq.irq_disable =
__PV_IS_CALLEE_SAVE(xen_irq_disable_direct);
pv_ops.irq.irq_enable =
diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c
index 850c93f346c7..dfa091d79c2e 100644
--- a/arch/x86/xen/irq.c
+++ b/arch/x86/xen/irq.c
@@ -42,28 +42,6 @@ asmlinkage __visible unsigned long xen_save_fl(void)
}
PV_CALLEE_SAVE_REGS_THUNK(xen_save_fl);
-__visible void xen_restore_fl(unsigned long flags)
-{
- struct vcpu_info *vcpu;
-
- /* convert from IF type flag */
- flags = !(flags & X86_EFLAGS_IF);
-
- /* See xen_irq_enable() for why preemption must be disabled. */
- preempt_disable();
- vcpu = this_cpu_read(xen_vcpu);
- vcpu->evtchn_upcall_mask = flags;
-
- if (flags == 0) {
- barrier(); /* unmask then check (avoid races) */
- if (unlikely(vcpu->evtchn_upcall_pending))
- xen_force_evtchn_callback();
- preempt_enable();
- } else
- preempt_enable_no_resched();
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_restore_fl);
-
asmlinkage __visible void xen_irq_disable(void)
{
/* There's a one instruction preempt window here. We need to
@@ -118,7 +96,6 @@ static void xen_halt(void)
static const struct pv_irq_ops xen_irq_ops __initconst = {
.save_fl = PV_CALLEE_SAVE(xen_save_fl),
- .restore_fl = PV_CALLEE_SAVE(xen_restore_fl),
.irq_disable = PV_CALLEE_SAVE(xen_irq_disable),
.irq_enable = PV_CALLEE_SAVE(xen_irq_enable),
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
index c0630fd9f44e..1ea7e41044b5 100644
--- a/arch/x86/xen/xen-asm.S
+++ b/arch/x86/xen/xen-asm.S
@@ -72,34 +72,6 @@ SYM_FUNC_START(xen_save_fl_direct)
ret
SYM_FUNC_END(xen_save_fl_direct)
-
-/*
- * In principle the caller should be passing us a value return from
- * xen_save_fl_direct, but for robustness sake we test only the
- * X86_EFLAGS_IF flag rather than the whole byte. After setting the
- * interrupt mask state, it checks for unmasked pending events and
- * enters the hypervisor to get them delivered if so.
- */
-SYM_FUNC_START(xen_restore_fl_direct)
- FRAME_BEGIN
- testw $X86_EFLAGS_IF, %di
- setz PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
- /*
- * Preempt here doesn't matter because that will deal with any
- * pending interrupts. The pending check may end up being run
- * on the wrong CPU, but that doesn't hurt.
- */
-
- /* check for unmasked and pending */
- cmpw $0x0001, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_pending
- jnz 1f
- call check_events
-1:
- FRAME_END
- ret
-SYM_FUNC_END(xen_restore_fl_direct)
-
-
/*
* Force an event check by making a hypercall, but preserve regs
* before making the call.
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index b2fd80a01a36..8d7ec49a35fb 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -131,7 +131,6 @@ static inline void __init xen_efi_init(struct boot_params *boot_params)
__visible void xen_irq_enable_direct(void);
__visible void xen_irq_disable_direct(void);
__visible unsigned long xen_save_fl_direct(void);
-__visible void xen_restore_fl_direct(unsigned long);
__visible unsigned long xen_read_cr2(void);
__visible unsigned long xen_read_cr2_direct(void);
--
2.26.2
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^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v4 07/15] x86/paravirt: switch time pvops functions to use static_call()
2021-01-20 13:25 [PATCH v4 00/15] x86: major paravirt cleanup Juergen Gross via Virtualization
` (2 preceding siblings ...)
2021-01-20 13:26 ` [PATCH v4 06/15] x86: rework arch_local_irq_restore() to not use popf Juergen Gross via Virtualization
@ 2021-01-20 13:26 ` Juergen Gross via Virtualization
2021-01-20 13:26 ` [PATCH v4 09/15] x86: add new features for paravirt patching Juergen Gross via Virtualization
` (6 subsequent siblings)
10 siblings, 0 replies; 15+ messages in thread
From: Juergen Gross via Virtualization @ 2021-01-20 13:26 UTC (permalink / raw)
To: bpetkov, x86, linux-kernel, linux-hyperv, virtualization, kvm
The time pvops functions are the only ones left which might be
used in 32-bit mode and which return a 64-bit value.
Switch them to use the static_call() mechanism instead of pvops, as
this allows quite some simplification of the pvops implementation.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V4:
- drop paravirt_time.h again
- don't move Hyper-V code (Michael Kelley)
---
arch/x86/Kconfig | 1 +
arch/x86/include/asm/mshyperv.h | 2 +-
arch/x86/include/asm/paravirt.h | 17 ++++++++++++++---
arch/x86/include/asm/paravirt_types.h | 6 ------
arch/x86/kernel/cpu/vmware.c | 5 +++--
arch/x86/kernel/kvm.c | 2 +-
arch/x86/kernel/kvmclock.c | 2 +-
arch/x86/kernel/paravirt.c | 16 ++++++++++++----
arch/x86/kernel/tsc.c | 2 +-
arch/x86/xen/time.c | 11 ++++-------
drivers/clocksource/hyperv_timer.c | 5 +++--
drivers/xen/time.c | 2 +-
12 files changed, 42 insertions(+), 29 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 21f851179ff0..7ccd4a80788c 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -771,6 +771,7 @@ if HYPERVISOR_GUEST
config PARAVIRT
bool "Enable paravirtualization code"
+ depends on HAVE_STATIC_CALL
help
This changes the kernel so it can modify itself when it is run
under a hypervisor, potentially improving performance significantly
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 30f76b966857..b4ee331d29a7 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -63,7 +63,7 @@ typedef int (*hyperv_fill_flush_list_func)(
static __always_inline void hv_setup_sched_clock(void *sched_clock)
{
#ifdef CONFIG_PARAVIRT
- pv_ops.time.sched_clock = sched_clock;
+ paravirt_set_sched_clock(sched_clock);
#endif
}
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 4abf110e2243..1e45b46fae84 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -15,11 +15,22 @@
#include <linux/bug.h>
#include <linux/types.h>
#include <linux/cpumask.h>
+#include <linux/static_call_types.h>
#include <asm/frame.h>
-static inline unsigned long long paravirt_sched_clock(void)
+u64 dummy_steal_clock(int cpu);
+u64 dummy_sched_clock(void);
+
+DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
+DECLARE_STATIC_CALL(pv_sched_clock, dummy_sched_clock);
+
+extern bool paravirt_using_native_sched_clock;
+
+void paravirt_set_sched_clock(u64 (*func)(void));
+
+static inline u64 paravirt_sched_clock(void)
{
- return PVOP_CALL0(unsigned long long, time.sched_clock);
+ return static_call(pv_sched_clock)();
}
struct static_key;
@@ -33,7 +44,7 @@ bool pv_is_native_vcpu_is_preempted(void);
static inline u64 paravirt_steal_clock(int cpu)
{
- return PVOP_CALL1(u64, time.steal_clock, cpu);
+ return static_call(pv_steal_clock)(cpu);
}
/* The paravirtualized I/O functions */
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index de87087d3bde..1fff349e4792 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -95,11 +95,6 @@ struct pv_lazy_ops {
} __no_randomize_layout;
#endif
-struct pv_time_ops {
- unsigned long long (*sched_clock)(void);
- unsigned long long (*steal_clock)(int cpu);
-} __no_randomize_layout;
-
struct pv_cpu_ops {
/* hooks for various privileged instructions */
void (*io_delay)(void);
@@ -291,7 +286,6 @@ struct pv_lock_ops {
* what to patch. */
struct paravirt_patch_template {
struct pv_init_ops init;
- struct pv_time_ops time;
struct pv_cpu_ops cpu;
struct pv_irq_ops irq;
struct pv_mmu_ops mmu;
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index c6ede3b3d302..84fb8e3f3d1b 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -27,6 +27,7 @@
#include <linux/clocksource.h>
#include <linux/cpu.h>
#include <linux/reboot.h>
+#include <linux/static_call.h>
#include <asm/div64.h>
#include <asm/x86_init.h>
#include <asm/hypervisor.h>
@@ -336,11 +337,11 @@ static void __init vmware_paravirt_ops_setup(void)
vmware_cyc2ns_setup();
if (vmw_sched_clock)
- pv_ops.time.sched_clock = vmware_sched_clock;
+ paravirt_set_sched_clock(vmware_sched_clock);
if (vmware_is_stealclock_available()) {
has_steal_clock = true;
- pv_ops.time.steal_clock = vmware_steal_clock;
+ static_call_update(pv_steal_clock, vmware_steal_clock);
/* We use reboot notifier only to disable steal clock */
register_reboot_notifier(&vmware_pv_reboot_nb);
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 5e78e01ca3b4..351ba99f6009 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -650,7 +650,7 @@ static void __init kvm_guest_init(void)
if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
has_steal_clock = 1;
- pv_ops.time.steal_clock = kvm_steal_clock;
+ static_call_update(pv_steal_clock, kvm_steal_clock);
}
if (pv_tlb_flush_supported()) {
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index aa593743acf6..01e7c1839ace 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -106,7 +106,7 @@ static inline void kvm_sched_clock_init(bool stable)
if (!stable)
clear_sched_clock_stable();
kvm_sched_clock_offset = kvm_clock_read();
- pv_ops.time.sched_clock = kvm_sched_clock_read;
+ paravirt_set_sched_clock(kvm_sched_clock_read);
pr_info("kvm-clock: using sched offset of %llu cycles",
kvm_sched_clock_offset);
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index c60222ab8ab9..44e5b0fe28cb 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -14,6 +14,7 @@
#include <linux/highmem.h>
#include <linux/kprobes.h>
#include <linux/pgtable.h>
+#include <linux/static_call.h>
#include <asm/bug.h>
#include <asm/paravirt.h>
@@ -167,6 +168,17 @@ static u64 native_steal_clock(int cpu)
return 0;
}
+DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock);
+DEFINE_STATIC_CALL(pv_sched_clock, native_sched_clock);
+
+bool paravirt_using_native_sched_clock = true;
+
+void paravirt_set_sched_clock(u64 (*func)(void))
+{
+ static_call_update(pv_sched_clock, func);
+ paravirt_using_native_sched_clock = (func == native_sched_clock);
+}
+
/* These are in entry.S */
extern void native_iret(void);
@@ -272,10 +284,6 @@ struct paravirt_patch_template pv_ops = {
/* Init ops. */
.init.patch = native_patch,
- /* Time ops. */
- .time.sched_clock = native_sched_clock,
- .time.steal_clock = native_steal_clock,
-
/* Cpu ops. */
.cpu.io_delay = native_io_delay,
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index f70dffc2771f..b6f7853d8077 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -254,7 +254,7 @@ unsigned long long sched_clock(void)
bool using_native_sched_clock(void)
{
- return pv_ops.time.sched_clock == native_sched_clock;
+ return paravirt_using_native_sched_clock;
}
#else
unsigned long long
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 91f5b330dcc6..01930e182e99 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -379,11 +379,6 @@ void xen_timer_resume(void)
}
}
-static const struct pv_time_ops xen_time_ops __initconst = {
- .sched_clock = xen_sched_clock,
- .steal_clock = xen_steal_clock,
-};
-
static struct pvclock_vsyscall_time_info *xen_clock __read_mostly;
static u64 xen_clock_value_saved;
@@ -528,7 +523,8 @@ static void __init xen_time_init(void)
void __init xen_init_time_ops(void)
{
xen_sched_clock_offset = xen_clocksource_read();
- pv_ops.time = xen_time_ops;
+ static_call_update(pv_steal_clock, xen_steal_clock);
+ paravirt_set_sched_clock(xen_sched_clock);
x86_init.timers.timer_init = xen_time_init;
x86_init.timers.setup_percpu_clockev = x86_init_noop;
@@ -570,7 +566,8 @@ void __init xen_hvm_init_time_ops(void)
}
xen_sched_clock_offset = xen_clocksource_read();
- pv_ops.time = xen_time_ops;
+ static_call_update(pv_steal_clock, xen_steal_clock);
+ paravirt_set_sched_clock(xen_sched_clock);
x86_init.timers.setup_percpu_clockev = xen_time_init;
x86_cpuinit.setup_percpu_clockev = xen_hvm_setup_cpu_clockevents;
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index ba04cb381cd3..bf3bf20bc6bd 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -18,6 +18,7 @@
#include <linux/sched_clock.h>
#include <linux/mm.h>
#include <linux/cpuhotplug.h>
+#include <linux/static_call.h>
#include <clocksource/hyperv_timer.h>
#include <asm/hyperv-tlfs.h>
#include <asm/mshyperv.h>
@@ -445,7 +446,7 @@ static bool __init hv_init_tsc_clocksource(void)
clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
hv_sched_clock_offset = hv_read_reference_counter();
- hv_setup_sched_clock(read_hv_sched_clock_tsc);
+ paravirt_set_sched_clock(read_hv_sched_clock_tsc);
return true;
}
@@ -470,6 +471,6 @@ void __init hv_init_clocksource(void)
clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
hv_sched_clock_offset = hv_read_reference_counter();
- hv_setup_sched_clock(read_hv_sched_clock_msr);
+ static_call_update(pv_sched_clock, read_hv_sched_clock_msr);
}
EXPORT_SYMBOL_GPL(hv_init_clocksource);
diff --git a/drivers/xen/time.c b/drivers/xen/time.c
index 108edbcbc040..199c016834ed 100644
--- a/drivers/xen/time.c
+++ b/drivers/xen/time.c
@@ -175,7 +175,7 @@ void __init xen_time_setup_guest(void)
xen_runstate_remote = !HYPERVISOR_vm_assist(VMASST_CMD_enable,
VMASST_TYPE_runstate_update_flag);
- pv_ops.time.steal_clock = xen_steal_clock;
+ static_call_update(pv_steal_clock, xen_steal_clock);
static_key_slow_inc(¶virt_steal_enabled);
if (xen_runstate_remote)
--
2.26.2
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^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v4 09/15] x86: add new features for paravirt patching
2021-01-20 13:25 [PATCH v4 00/15] x86: major paravirt cleanup Juergen Gross via Virtualization
` (3 preceding siblings ...)
2021-01-20 13:26 ` [PATCH v4 07/15] x86/paravirt: switch time pvops functions to use static_call() Juergen Gross via Virtualization
@ 2021-01-20 13:26 ` Juergen Gross via Virtualization
2021-01-20 13:26 ` [PATCH v4 10/15] x86/paravirt: remove no longer needed 32-bit pvops cruft Juergen Gross via Virtualization
` (5 subsequent siblings)
10 siblings, 0 replies; 15+ messages in thread
From: Juergen Gross via Virtualization @ 2021-01-20 13:26 UTC (permalink / raw)
To: bpetkov, x86, linux-kernel, virtualization
For being able to switch paravirt patching from special cased custom
code sequences to ALTERNATIVE handling some X86_FEATURE_* are needed
as new features. This enables to have the standard indirect pv call
as the default code and to patch that with the non-Xen custom code
sequence via ALTERNATIVE patching later.
Make sure paravirt patching is performed before alternative patching.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V3:
- add comment (Boris Petkov)
- no negative features (Boris Petkov)
V4:
- move paravirt_set_cap() to paravirt-spinlocks.c
---
arch/x86/include/asm/cpufeatures.h | 2 ++
arch/x86/include/asm/paravirt.h | 10 ++++++++++
arch/x86/kernel/alternative.c | 30 ++++++++++++++++++++++++++--
arch/x86/kernel/paravirt-spinlocks.c | 9 +++++++++
4 files changed, 49 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 84b887825f12..3ae8944b253a 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -238,6 +238,8 @@
#define X86_FEATURE_VMW_VMMCALL ( 8*32+19) /* "" VMware prefers VMMCALL hypercall instruction */
#define X86_FEATURE_SEV_ES ( 8*32+20) /* AMD Secure Encrypted Virtualization - Encrypted State */
#define X86_FEATURE_VM_PAGE_FLUSH ( 8*32+21) /* "" VM Page Flush MSR is supported */
+#define X86_FEATURE_PVUNLOCK ( 8*32+22) /* "" PV unlock function */
+#define X86_FEATURE_VCPUPREEMPT ( 8*32+23) /* "" PV vcpu_is_preempted function */
/* Intel-defined CPU features, CPUID level 0x00000007:0 (EBX), word 9 */
#define X86_FEATURE_FSGSBASE ( 9*32+ 0) /* RDFSBASE, WRFSBASE, RDGSBASE, WRGSBASE instructions*/
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 1e45b46fae84..8c354099d9c3 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -47,6 +47,10 @@ static inline u64 paravirt_steal_clock(int cpu)
return static_call(pv_steal_clock)(cpu);
}
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+void __init paravirt_set_cap(void);
+#endif
+
/* The paravirtualized I/O functions */
static inline void slow_down_io(void)
{
@@ -811,5 +815,11 @@ static inline void paravirt_arch_exit_mmap(struct mm_struct *mm)
{
}
#endif
+
+#ifndef CONFIG_PARAVIRT_SPINLOCKS
+static inline void paravirt_set_cap(void)
+{
+}
+#endif
#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_PARAVIRT_H */
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 0a904fb2678b..221acb2b868a 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -28,6 +28,7 @@
#include <asm/insn.h>
#include <asm/io.h>
#include <asm/fixmap.h>
+#include <asm/paravirt.h>
int __read_mostly alternatives_patched;
@@ -730,6 +731,33 @@ void __init alternative_instructions(void)
* patching.
*/
+ /*
+ * Paravirt patching and alternative patching can be combined to
+ * replace a function call with a short direct code sequence (e.g.
+ * by setting a constant return value instead of doing that in an
+ * external function).
+ * In order to make this work the following sequence is required:
+ * 1. set (artificial) features depending on used paravirt
+ * functions which can later influence alternative patching
+ * 2. apply paravirt patching (generally replacing an indirect
+ * function call with a direct one)
+ * 3. apply alternative patching (e.g. replacing a direct function
+ * call with a custom code sequence)
+ * Doing paravirt patching after alternative patching would clobber
+ * the optimization of the custom code with a function call again.
+ */
+ paravirt_set_cap();
+
+ /*
+ * First patch paravirt functions, such that we overwrite the indirect
+ * call with the direct call.
+ */
+ apply_paravirt(__parainstructions, __parainstructions_end);
+
+ /*
+ * Then patch alternatives, such that those paravirt calls that are in
+ * alternatives can be overwritten by their immediate fragments.
+ */
apply_alternatives(__alt_instructions, __alt_instructions_end);
#ifdef CONFIG_SMP
@@ -748,8 +776,6 @@ void __init alternative_instructions(void)
}
#endif
- apply_paravirt(__parainstructions, __parainstructions_end);
-
restart_nmi();
alternatives_patched = 1;
}
diff --git a/arch/x86/kernel/paravirt-spinlocks.c b/arch/x86/kernel/paravirt-spinlocks.c
index 4f75d0cf6305..9e1ea99ad9df 100644
--- a/arch/x86/kernel/paravirt-spinlocks.c
+++ b/arch/x86/kernel/paravirt-spinlocks.c
@@ -32,3 +32,12 @@ bool pv_is_native_vcpu_is_preempted(void)
return pv_ops.lock.vcpu_is_preempted.func ==
__raw_callee_save___native_vcpu_is_preempted;
}
+
+void __init paravirt_set_cap(void)
+{
+ if (!pv_is_native_spin_unlock())
+ setup_force_cpu_cap(X86_FEATURE_PVUNLOCK);
+
+ if (!pv_is_native_vcpu_is_preempted())
+ setup_force_cpu_cap(X86_FEATURE_VCPUPREEMPT);
+}
--
2.26.2
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^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v4 10/15] x86/paravirt: remove no longer needed 32-bit pvops cruft
2021-01-20 13:25 [PATCH v4 00/15] x86: major paravirt cleanup Juergen Gross via Virtualization
` (4 preceding siblings ...)
2021-01-20 13:26 ` [PATCH v4 09/15] x86: add new features for paravirt patching Juergen Gross via Virtualization
@ 2021-01-20 13:26 ` Juergen Gross via Virtualization
2021-01-20 13:26 ` [PATCH v4 11/15] x86/paravirt: simplify paravirt macros Juergen Gross via Virtualization
` (4 subsequent siblings)
10 siblings, 0 replies; 15+ messages in thread
From: Juergen Gross via Virtualization @ 2021-01-20 13:26 UTC (permalink / raw)
To: bpetkov, x86, linux-kernel, virtualization
PVOP_VCALL4() is only used for Xen PV, while PVOP_CALL4() isn't used
at all. Keep PVOP_CALL4() for 64 bits due to symmetry reasons.
This allows to remove the 32-bit definitions of those macros leading
to a substantial simplification of the paravirt macros, as those were
the only ones needing non-empty "pre" and "post" parameters.
PVOP_CALLEE2() and PVOP_VCALLEE2() are used nowhere, so remove them.
Another no longer needed case is special handling of return types
larger than unsigned long. Replace that with a BUILD_BUG_ON().
DISABLE_INTERRUPTS() is used in 32-bit code only, so it can just be
replaced by cli.
INTERRUPT_RETURN in 32-bit code can be replaced by iret.
ENABLE_INTERRUPTS is used nowhere, so it can be removed.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/x86/entry/entry_32.S | 4 +-
arch/x86/include/asm/irqflags.h | 5 --
arch/x86/include/asm/paravirt.h | 35 +-------
arch/x86/include/asm/paravirt_types.h | 112 ++++++++------------------
arch/x86/kernel/asm-offsets.c | 2 -
5 files changed, 35 insertions(+), 123 deletions(-)
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index df8c017e6161..765487e57d6e 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -430,7 +430,7 @@
* will soon execute iret and the tracer was already set to
* the irqstate after the IRET:
*/
- DISABLE_INTERRUPTS(CLBR_ANY)
+ cli
lss (%esp), %esp /* switch to espfix segment */
.Lend_\@:
#endif /* CONFIG_X86_ESPFIX32 */
@@ -1077,7 +1077,7 @@ restore_all_switch_stack:
* when returning from IPI handler and when returning from
* scheduler to user-space.
*/
- INTERRUPT_RETURN
+ iret
.section .fixup, "ax"
SYM_CODE_START(asm_iret_error)
diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index 144d70ea4393..a0efbcd24b86 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -109,9 +109,6 @@ static __always_inline unsigned long arch_local_irq_save(void)
}
#else
-#define ENABLE_INTERRUPTS(x) sti
-#define DISABLE_INTERRUPTS(x) cli
-
#ifdef CONFIG_X86_64
#ifdef CONFIG_DEBUG_ENTRY
#define SAVE_FLAGS(x) pushfq; popq %rax
@@ -119,8 +116,6 @@ static __always_inline unsigned long arch_local_irq_save(void)
#define INTERRUPT_RETURN jmp native_iret
-#else
-#define INTERRUPT_RETURN iret
#endif
#endif /* __ASSEMBLY__ */
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 8c354099d9c3..c6496a82fad1 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -721,6 +721,7 @@ extern void default_banner(void);
.if ((~(set)) & mask); pop %reg; .endif
#ifdef CONFIG_X86_64
+#ifdef CONFIG_PARAVIRT_XXL
#define PV_SAVE_REGS(set) \
COND_PUSH(set, CLBR_RAX, rax); \
@@ -746,46 +747,12 @@ extern void default_banner(void);
#define PARA_PATCH(off) ((off) / 8)
#define PARA_SITE(ptype, ops) _PVSITE(ptype, ops, .quad, 8)
#define PARA_INDIRECT(addr) *addr(%rip)
-#else
-#define PV_SAVE_REGS(set) \
- COND_PUSH(set, CLBR_EAX, eax); \
- COND_PUSH(set, CLBR_EDI, edi); \
- COND_PUSH(set, CLBR_ECX, ecx); \
- COND_PUSH(set, CLBR_EDX, edx)
-#define PV_RESTORE_REGS(set) \
- COND_POP(set, CLBR_EDX, edx); \
- COND_POP(set, CLBR_ECX, ecx); \
- COND_POP(set, CLBR_EDI, edi); \
- COND_POP(set, CLBR_EAX, eax)
-
-#define PARA_PATCH(off) ((off) / 4)
-#define PARA_SITE(ptype, ops) _PVSITE(ptype, ops, .long, 4)
-#define PARA_INDIRECT(addr) *%cs:addr
-#endif
-#ifdef CONFIG_PARAVIRT_XXL
#define INTERRUPT_RETURN \
PARA_SITE(PARA_PATCH(PV_CPU_iret), \
ANNOTATE_RETPOLINE_SAFE; \
jmp PARA_INDIRECT(pv_ops+PV_CPU_iret);)
-#define DISABLE_INTERRUPTS(clobbers) \
- PARA_SITE(PARA_PATCH(PV_IRQ_irq_disable), \
- PV_SAVE_REGS(clobbers | CLBR_CALLEE_SAVE); \
- ANNOTATE_RETPOLINE_SAFE; \
- call PARA_INDIRECT(pv_ops+PV_IRQ_irq_disable); \
- PV_RESTORE_REGS(clobbers | CLBR_CALLEE_SAVE);)
-
-#define ENABLE_INTERRUPTS(clobbers) \
- PARA_SITE(PARA_PATCH(PV_IRQ_irq_enable), \
- PV_SAVE_REGS(clobbers | CLBR_CALLEE_SAVE); \
- ANNOTATE_RETPOLINE_SAFE; \
- call PARA_INDIRECT(pv_ops+PV_IRQ_irq_enable); \
- PV_RESTORE_REGS(clobbers | CLBR_CALLEE_SAVE);)
-#endif
-
-#ifdef CONFIG_X86_64
-#ifdef CONFIG_PARAVIRT_XXL
#ifdef CONFIG_DEBUG_ENTRY
#define SAVE_FLAGS(clobbers) \
PARA_SITE(PARA_PATCH(PV_IRQ_save_fl), \
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 1fff349e4792..42f9eef84131 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -470,55 +470,34 @@ int paravirt_disable_iospace(void);
})
-#define ____PVOP_CALL(rettype, op, clbr, call_clbr, extra_clbr, \
- pre, post, ...) \
+#define ____PVOP_CALL(rettype, op, clbr, call_clbr, extra_clbr, ...) \
({ \
- rettype __ret; \
PVOP_CALL_ARGS; \
PVOP_TEST_NULL(op); \
- /* This is 32-bit specific, but is okay in 64-bit */ \
- /* since this condition will never hold */ \
- if (sizeof(rettype) > sizeof(unsigned long)) { \
- asm volatile(pre \
- paravirt_alt(PARAVIRT_CALL) \
- post \
- : call_clbr, ASM_CALL_CONSTRAINT \
- : paravirt_type(op), \
- paravirt_clobber(clbr), \
- ##__VA_ARGS__ \
- : "memory", "cc" extra_clbr); \
- __ret = (rettype)((((u64)__edx) << 32) | __eax); \
- } else { \
- asm volatile(pre \
- paravirt_alt(PARAVIRT_CALL) \
- post \
- : call_clbr, ASM_CALL_CONSTRAINT \
- : paravirt_type(op), \
- paravirt_clobber(clbr), \
- ##__VA_ARGS__ \
- : "memory", "cc" extra_clbr); \
- __ret = (rettype)(__eax & PVOP_RETMASK(rettype)); \
- } \
- __ret; \
+ BUILD_BUG_ON(sizeof(rettype) > sizeof(unsigned long)); \
+ asm volatile(paravirt_alt(PARAVIRT_CALL) \
+ : call_clbr, ASM_CALL_CONSTRAINT \
+ : paravirt_type(op), \
+ paravirt_clobber(clbr), \
+ ##__VA_ARGS__ \
+ : "memory", "cc" extra_clbr); \
+ (rettype)(__eax & PVOP_RETMASK(rettype)); \
})
-#define __PVOP_CALL(rettype, op, pre, post, ...) \
+#define __PVOP_CALL(rettype, op, ...) \
____PVOP_CALL(rettype, op, CLBR_ANY, PVOP_CALL_CLOBBERS, \
- EXTRA_CLOBBERS, pre, post, ##__VA_ARGS__)
+ EXTRA_CLOBBERS, ##__VA_ARGS__)
-#define __PVOP_CALLEESAVE(rettype, op, pre, post, ...) \
+#define __PVOP_CALLEESAVE(rettype, op, ...) \
____PVOP_CALL(rettype, op.func, CLBR_RET_REG, \
- PVOP_CALLEE_CLOBBERS, , \
- pre, post, ##__VA_ARGS__)
+ PVOP_CALLEE_CLOBBERS, , ##__VA_ARGS__)
-#define ____PVOP_VCALL(op, clbr, call_clbr, extra_clbr, pre, post, ...) \
+#define ____PVOP_VCALL(op, clbr, call_clbr, extra_clbr, ...) \
({ \
PVOP_VCALL_ARGS; \
PVOP_TEST_NULL(op); \
- asm volatile(pre \
- paravirt_alt(PARAVIRT_CALL) \
- post \
+ asm volatile(paravirt_alt(PARAVIRT_CALL) \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
paravirt_clobber(clbr), \
@@ -526,84 +505,57 @@ int paravirt_disable_iospace(void);
: "memory", "cc" extra_clbr); \
})
-#define __PVOP_VCALL(op, pre, post, ...) \
+#define __PVOP_VCALL(op, ...) \
____PVOP_VCALL(op, CLBR_ANY, PVOP_VCALL_CLOBBERS, \
- VEXTRA_CLOBBERS, \
- pre, post, ##__VA_ARGS__)
+ VEXTRA_CLOBBERS, ##__VA_ARGS__)
-#define __PVOP_VCALLEESAVE(op, pre, post, ...) \
+#define __PVOP_VCALLEESAVE(op, ...) \
____PVOP_VCALL(op.func, CLBR_RET_REG, \
- PVOP_VCALLEE_CLOBBERS, , \
- pre, post, ##__VA_ARGS__)
+ PVOP_VCALLEE_CLOBBERS, , ##__VA_ARGS__)
#define PVOP_CALL0(rettype, op) \
- __PVOP_CALL(rettype, op, "", "")
+ __PVOP_CALL(rettype, op)
#define PVOP_VCALL0(op) \
- __PVOP_VCALL(op, "", "")
+ __PVOP_VCALL(op)
#define PVOP_CALLEE0(rettype, op) \
- __PVOP_CALLEESAVE(rettype, op, "", "")
+ __PVOP_CALLEESAVE(rettype, op)
#define PVOP_VCALLEE0(op) \
- __PVOP_VCALLEESAVE(op, "", "")
+ __PVOP_VCALLEESAVE(op)
#define PVOP_CALL1(rettype, op, arg1) \
- __PVOP_CALL(rettype, op, "", "", PVOP_CALL_ARG1(arg1))
+ __PVOP_CALL(rettype, op, PVOP_CALL_ARG1(arg1))
#define PVOP_VCALL1(op, arg1) \
- __PVOP_VCALL(op, "", "", PVOP_CALL_ARG1(arg1))
+ __PVOP_VCALL(op, PVOP_CALL_ARG1(arg1))
#define PVOP_CALLEE1(rettype, op, arg1) \
- __PVOP_CALLEESAVE(rettype, op, "", "", PVOP_CALL_ARG1(arg1))
+ __PVOP_CALLEESAVE(rettype, op, PVOP_CALL_ARG1(arg1))
#define PVOP_VCALLEE1(op, arg1) \
- __PVOP_VCALLEESAVE(op, "", "", PVOP_CALL_ARG1(arg1))
+ __PVOP_VCALLEESAVE(op, PVOP_CALL_ARG1(arg1))
#define PVOP_CALL2(rettype, op, arg1, arg2) \
- __PVOP_CALL(rettype, op, "", "", PVOP_CALL_ARG1(arg1), \
- PVOP_CALL_ARG2(arg2))
+ __PVOP_CALL(rettype, op, PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2))
#define PVOP_VCALL2(op, arg1, arg2) \
- __PVOP_VCALL(op, "", "", PVOP_CALL_ARG1(arg1), \
- PVOP_CALL_ARG2(arg2))
-
-#define PVOP_CALLEE2(rettype, op, arg1, arg2) \
- __PVOP_CALLEESAVE(rettype, op, "", "", PVOP_CALL_ARG1(arg1), \
- PVOP_CALL_ARG2(arg2))
-#define PVOP_VCALLEE2(op, arg1, arg2) \
- __PVOP_VCALLEESAVE(op, "", "", PVOP_CALL_ARG1(arg1), \
- PVOP_CALL_ARG2(arg2))
-
+ __PVOP_VCALL(op, PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2))
#define PVOP_CALL3(rettype, op, arg1, arg2, arg3) \
- __PVOP_CALL(rettype, op, "", "", PVOP_CALL_ARG1(arg1), \
+ __PVOP_CALL(rettype, op, PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2), PVOP_CALL_ARG3(arg3))
#define PVOP_VCALL3(op, arg1, arg2, arg3) \
- __PVOP_VCALL(op, "", "", PVOP_CALL_ARG1(arg1), \
+ __PVOP_VCALL(op, PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2), PVOP_CALL_ARG3(arg3))
-/* This is the only difference in x86_64. We can make it much simpler */
-#ifdef CONFIG_X86_32
#define PVOP_CALL4(rettype, op, arg1, arg2, arg3, arg4) \
__PVOP_CALL(rettype, op, \
- "push %[_arg4];", "lea 4(%%esp),%%esp;", \
- PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2), \
- PVOP_CALL_ARG3(arg3), [_arg4] "mr" ((u32)(arg4)))
-#define PVOP_VCALL4(op, arg1, arg2, arg3, arg4) \
- __PVOP_VCALL(op, \
- "push %[_arg4];", "lea 4(%%esp),%%esp;", \
- "0" ((u32)(arg1)), "1" ((u32)(arg2)), \
- "2" ((u32)(arg3)), [_arg4] "mr" ((u32)(arg4)))
-#else
-#define PVOP_CALL4(rettype, op, arg1, arg2, arg3, arg4) \
- __PVOP_CALL(rettype, op, "", "", \
PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2), \
PVOP_CALL_ARG3(arg3), PVOP_CALL_ARG4(arg4))
#define PVOP_VCALL4(op, arg1, arg2, arg3, arg4) \
- __PVOP_VCALL(op, "", "", \
- PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2), \
+ __PVOP_VCALL(op, PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2), \
PVOP_CALL_ARG3(arg3), PVOP_CALL_ARG4(arg4))
-#endif
/* Lazy mode for batching updates / context switch */
enum paravirt_lazy_mode {
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index 60b9f42ce3c1..736508004b30 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -63,8 +63,6 @@ static void __used common(void)
#ifdef CONFIG_PARAVIRT_XXL
BLANK();
- OFFSET(PV_IRQ_irq_disable, paravirt_patch_template, irq.irq_disable);
- OFFSET(PV_IRQ_irq_enable, paravirt_patch_template, irq.irq_enable);
OFFSET(PV_CPU_iret, paravirt_patch_template, cpu.iret);
#endif
--
2.26.2
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^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v4 11/15] x86/paravirt: simplify paravirt macros
2021-01-20 13:25 [PATCH v4 00/15] x86: major paravirt cleanup Juergen Gross via Virtualization
` (5 preceding siblings ...)
2021-01-20 13:26 ` [PATCH v4 10/15] x86/paravirt: remove no longer needed 32-bit pvops cruft Juergen Gross via Virtualization
@ 2021-01-20 13:26 ` Juergen Gross via Virtualization
2021-01-20 13:26 ` [PATCH v4 12/15] x86/paravirt: switch iret pvops to ALTERNATIVE Juergen Gross via Virtualization
` (3 subsequent siblings)
10 siblings, 0 replies; 15+ messages in thread
From: Juergen Gross via Virtualization @ 2021-01-20 13:26 UTC (permalink / raw)
To: bpetkov, x86, virtualization, linux-kernel, clang-built-linux
The central pvops call macros ____PVOP_CALL() and ____PVOP_VCALL() are
looking very similar now.
The main differences are using PVOP_VCALL_ARGS or PVOP_CALL_ARGS, which
are identical, and the return value handling.
So drop PVOP_VCALL_ARGS and instead of ____PVOP_VCALL() just use
(void)____PVOP_CALL(long, ...).
Note that it isn't easily possible to just redefine ____PVOP_VCALL()
to use ____PVOP_CALL() instead, as this would require further hiding of
commas in macro parameters.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V3:
- new patch
V4:
- fix build warnings with clang (kernel test robot)
---
arch/x86/include/asm/paravirt_types.h | 41 ++++++++-------------------
1 file changed, 12 insertions(+), 29 deletions(-)
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 42f9eef84131..45bd21647dd8 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -408,11 +408,9 @@ int paravirt_disable_iospace(void);
* makes sure the incoming and outgoing types are always correct.
*/
#ifdef CONFIG_X86_32
-#define PVOP_VCALL_ARGS \
+#define PVOP_CALL_ARGS \
unsigned long __eax = __eax, __edx = __edx, __ecx = __ecx;
-#define PVOP_CALL_ARGS PVOP_VCALL_ARGS
-
#define PVOP_CALL_ARG1(x) "a" ((unsigned long)(x))
#define PVOP_CALL_ARG2(x) "d" ((unsigned long)(x))
#define PVOP_CALL_ARG3(x) "c" ((unsigned long)(x))
@@ -428,12 +426,10 @@ int paravirt_disable_iospace(void);
#define VEXTRA_CLOBBERS
#else /* CONFIG_X86_64 */
/* [re]ax isn't an arg, but the return val */
-#define PVOP_VCALL_ARGS \
+#define PVOP_CALL_ARGS \
unsigned long __edi = __edi, __esi = __esi, \
__edx = __edx, __ecx = __ecx, __eax = __eax;
-#define PVOP_CALL_ARGS PVOP_VCALL_ARGS
-
#define PVOP_CALL_ARG1(x) "D" ((unsigned long)(x))
#define PVOP_CALL_ARG2(x) "S" ((unsigned long)(x))
#define PVOP_CALL_ARG3(x) "d" ((unsigned long)(x))
@@ -458,59 +454,46 @@ int paravirt_disable_iospace(void);
#define PVOP_TEST_NULL(op) ((void)pv_ops.op)
#endif
-#define PVOP_RETMASK(rettype) \
+#define PVOP_RETVAL(rettype) \
({ unsigned long __mask = ~0UL; \
+ BUILD_BUG_ON(sizeof(rettype) > sizeof(unsigned long)); \
switch (sizeof(rettype)) { \
case 1: __mask = 0xffUL; break; \
case 2: __mask = 0xffffUL; break; \
case 4: __mask = 0xffffffffUL; break; \
default: break; \
} \
- __mask; \
+ __mask & __eax; \
})
-#define ____PVOP_CALL(rettype, op, clbr, call_clbr, extra_clbr, ...) \
+#define ____PVOP_CALL(ret, op, clbr, call_clbr, extra_clbr, ...) \
({ \
PVOP_CALL_ARGS; \
PVOP_TEST_NULL(op); \
- BUILD_BUG_ON(sizeof(rettype) > sizeof(unsigned long)); \
asm volatile(paravirt_alt(PARAVIRT_CALL) \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
paravirt_clobber(clbr), \
##__VA_ARGS__ \
: "memory", "cc" extra_clbr); \
- (rettype)(__eax & PVOP_RETMASK(rettype)); \
+ ret; \
})
#define __PVOP_CALL(rettype, op, ...) \
- ____PVOP_CALL(rettype, op, CLBR_ANY, PVOP_CALL_CLOBBERS, \
- EXTRA_CLOBBERS, ##__VA_ARGS__)
+ ____PVOP_CALL(PVOP_RETVAL(rettype), op, CLBR_ANY, \
+ PVOP_CALL_CLOBBERS, EXTRA_CLOBBERS, ##__VA_ARGS__)
#define __PVOP_CALLEESAVE(rettype, op, ...) \
- ____PVOP_CALL(rettype, op.func, CLBR_RET_REG, \
+ ____PVOP_CALL(PVOP_RETVAL(rettype), op.func, CLBR_RET_REG, \
PVOP_CALLEE_CLOBBERS, , ##__VA_ARGS__)
-
-#define ____PVOP_VCALL(op, clbr, call_clbr, extra_clbr, ...) \
- ({ \
- PVOP_VCALL_ARGS; \
- PVOP_TEST_NULL(op); \
- asm volatile(paravirt_alt(PARAVIRT_CALL) \
- : call_clbr, ASM_CALL_CONSTRAINT \
- : paravirt_type(op), \
- paravirt_clobber(clbr), \
- ##__VA_ARGS__ \
- : "memory", "cc" extra_clbr); \
- })
-
#define __PVOP_VCALL(op, ...) \
- ____PVOP_VCALL(op, CLBR_ANY, PVOP_VCALL_CLOBBERS, \
+ (void)____PVOP_CALL(, op, CLBR_ANY, PVOP_VCALL_CLOBBERS, \
VEXTRA_CLOBBERS, ##__VA_ARGS__)
#define __PVOP_VCALLEESAVE(op, ...) \
- ____PVOP_VCALL(op.func, CLBR_RET_REG, \
+ (void)____PVOP_CALL(, op.func, CLBR_RET_REG, \
PVOP_VCALLEE_CLOBBERS, , ##__VA_ARGS__)
--
2.26.2
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^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v4 12/15] x86/paravirt: switch iret pvops to ALTERNATIVE
2021-01-20 13:25 [PATCH v4 00/15] x86: major paravirt cleanup Juergen Gross via Virtualization
` (6 preceding siblings ...)
2021-01-20 13:26 ` [PATCH v4 11/15] x86/paravirt: simplify paravirt macros Juergen Gross via Virtualization
@ 2021-01-20 13:26 ` Juergen Gross via Virtualization
2021-01-20 13:26 ` [PATCH v4 13/15] x86/paravirt: add new macros PVOP_ALT* supporting pvops in ALTERNATIVEs Juergen Gross via Virtualization
` (2 subsequent siblings)
10 siblings, 0 replies; 15+ messages in thread
From: Juergen Gross via Virtualization @ 2021-01-20 13:26 UTC (permalink / raw)
To: bpetkov, x86, virtualization, linux-kernel
The iret paravirt op is rather special as it is using a jmp instead
of a call instruction. Switch it to ALTERNATIVE.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V3:
- use ALTERNATIVE_TERNARY
---
arch/x86/include/asm/paravirt.h | 6 +++---
arch/x86/include/asm/paravirt_types.h | 5 +----
arch/x86/kernel/asm-offsets.c | 5 -----
arch/x86/kernel/paravirt.c | 26 ++------------------------
arch/x86/xen/enlighten_pv.c | 3 +--
5 files changed, 7 insertions(+), 38 deletions(-)
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index c6496a82fad1..36cd71fa097f 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -749,9 +749,9 @@ extern void default_banner(void);
#define PARA_INDIRECT(addr) *addr(%rip)
#define INTERRUPT_RETURN \
- PARA_SITE(PARA_PATCH(PV_CPU_iret), \
- ANNOTATE_RETPOLINE_SAFE; \
- jmp PARA_INDIRECT(pv_ops+PV_CPU_iret);)
+ ANNOTATE_RETPOLINE_SAFE; \
+ ALTERNATIVE_TERNARY("jmp *paravirt_iret(%rip);", \
+ X86_FEATURE_XENPV, "jmp xen_iret;", "jmp native_iret;")
#ifdef CONFIG_DEBUG_ENTRY
#define SAVE_FLAGS(clobbers) \
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 45bd21647dd8..0afdac83f926 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -151,10 +151,6 @@ struct pv_cpu_ops {
u64 (*read_pmc)(int counter);
- /* Normal iret. Jump to this with the standard iret stack
- frame set up. */
- void (*iret)(void);
-
void (*start_context_switch)(struct task_struct *prev);
void (*end_context_switch)(struct task_struct *next);
#endif
@@ -294,6 +290,7 @@ struct paravirt_patch_template {
extern struct pv_info pv_info;
extern struct paravirt_patch_template pv_ops;
+extern void (*paravirt_iret)(void);
#define PARAVIRT_PATCH(x) \
(offsetof(struct paravirt_patch_template, x) / sizeof(void *))
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index 736508004b30..ecd3fd6993d1 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -61,11 +61,6 @@ static void __used common(void)
OFFSET(IA32_RT_SIGFRAME_sigcontext, rt_sigframe_ia32, uc.uc_mcontext);
#endif
-#ifdef CONFIG_PARAVIRT_XXL
- BLANK();
- OFFSET(PV_CPU_iret, paravirt_patch_template, cpu.iret);
-#endif
-
#ifdef CONFIG_XEN
BLANK();
OFFSET(XEN_vcpu_info_mask, vcpu_info, evtchn_upcall_mask);
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 44e5b0fe28cb..0553a339d850 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -86,25 +86,6 @@ u64 notrace _paravirt_ident_64(u64 x)
{
return x;
}
-
-static unsigned paravirt_patch_jmp(void *insn_buff, const void *target,
- unsigned long addr, unsigned len)
-{
- struct branch *b = insn_buff;
- unsigned long delta = (unsigned long)target - (addr+5);
-
- if (len < 5) {
-#ifdef CONFIG_RETPOLINE
- WARN_ONCE(1, "Failing to patch indirect JMP in %ps\n", (void *)addr);
-#endif
- return len; /* call too long for patch site */
- }
-
- b->opcode = 0xe9; /* jmp */
- b->delta = delta;
-
- return 5;
-}
#endif
DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key);
@@ -136,9 +117,6 @@ unsigned paravirt_patch_default(u8 type, void *insn_buff,
else if (opfunc == _paravirt_ident_64)
ret = paravirt_patch_ident_64(insn_buff, len);
- else if (type == PARAVIRT_PATCH(cpu.iret))
- /* If operation requires a jmp, then jmp */
- ret = paravirt_patch_jmp(insn_buff, opfunc, addr, len);
#endif
else
/* Otherwise call the function. */
@@ -316,8 +294,6 @@ struct paravirt_patch_template pv_ops = {
.cpu.load_sp0 = native_load_sp0,
- .cpu.iret = native_iret,
-
#ifdef CONFIG_X86_IOPL_IOPERM
.cpu.invalidate_io_bitmap = native_tss_invalidate_io_bitmap,
.cpu.update_io_bitmap = native_tss_update_io_bitmap,
@@ -422,6 +398,8 @@ struct paravirt_patch_template pv_ops = {
NOKPROBE_SYMBOL(native_get_debugreg);
NOKPROBE_SYMBOL(native_set_debugreg);
NOKPROBE_SYMBOL(native_load_idt);
+
+void (*paravirt_iret)(void) = native_iret;
#endif
EXPORT_SYMBOL(pv_ops);
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 32b295cc2716..4716383c64a9 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -1057,8 +1057,6 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = {
.read_pmc = xen_read_pmc,
- .iret = xen_iret,
-
.load_tr_desc = paravirt_nop,
.set_ldt = xen_set_ldt,
.load_gdt = xen_load_gdt,
@@ -1222,6 +1220,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
pv_info = xen_info;
pv_ops.init.patch = paravirt_patch_default;
pv_ops.cpu = xen_cpu_ops;
+ paravirt_iret = xen_iret;
xen_init_irq_ops();
/*
--
2.26.2
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^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v4 13/15] x86/paravirt: add new macros PVOP_ALT* supporting pvops in ALTERNATIVEs
2021-01-20 13:25 [PATCH v4 00/15] x86: major paravirt cleanup Juergen Gross via Virtualization
` (7 preceding siblings ...)
2021-01-20 13:26 ` [PATCH v4 12/15] x86/paravirt: switch iret pvops to ALTERNATIVE Juergen Gross via Virtualization
@ 2021-01-20 13:26 ` Juergen Gross via Virtualization
2021-01-20 13:26 ` [PATCH v4 14/15] x86/paravirt: switch functions with custom code to ALTERNATIVE Juergen Gross via Virtualization
2021-01-20 13:26 ` [PATCH v4 15/15] x86/paravirt: have only one paravirt patch function Juergen Gross via Virtualization
10 siblings, 0 replies; 15+ messages in thread
From: Juergen Gross via Virtualization @ 2021-01-20 13:26 UTC (permalink / raw)
To: bpetkov, x86, virtualization, linux-kernel
Instead of using paravirt patching for custom code sequences add
support for using ALTERNATIVE handling combined with paravirt call
patching.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V3:
- drop ____PVOP_ALT_VCALL() macro
---
arch/x86/include/asm/paravirt_types.h | 49 ++++++++++++++++++++++++++-
1 file changed, 48 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 0afdac83f926..0ed976286d49 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -477,44 +477,91 @@ int paravirt_disable_iospace(void);
ret; \
})
+#define ____PVOP_ALT_CALL(ret, op, alt, cond, clbr, call_clbr, \
+ extra_clbr, ...) \
+ ({ \
+ PVOP_CALL_ARGS; \
+ PVOP_TEST_NULL(op); \
+ asm volatile(ALTERNATIVE(paravirt_alt(PARAVIRT_CALL), \
+ alt, cond) \
+ : call_clbr, ASM_CALL_CONSTRAINT \
+ : paravirt_type(op), \
+ paravirt_clobber(clbr), \
+ ##__VA_ARGS__ \
+ : "memory", "cc" extra_clbr); \
+ ret; \
+ })
+
#define __PVOP_CALL(rettype, op, ...) \
____PVOP_CALL(PVOP_RETVAL(rettype), op, CLBR_ANY, \
PVOP_CALL_CLOBBERS, EXTRA_CLOBBERS, ##__VA_ARGS__)
+#define __PVOP_ALT_CALL(rettype, op, alt, cond, ...) \
+ ____PVOP_ALT_CALL(PVOP_RETVAL(rettype), op, alt, cond, CLBR_ANY,\
+ PVOP_CALL_CLOBBERS, EXTRA_CLOBBERS, \
+ ##__VA_ARGS__)
+
#define __PVOP_CALLEESAVE(rettype, op, ...) \
____PVOP_CALL(PVOP_RETVAL(rettype), op.func, CLBR_RET_REG, \
PVOP_CALLEE_CLOBBERS, , ##__VA_ARGS__)
+#define __PVOP_ALT_CALLEESAVE(rettype, op, alt, cond, ...) \
+ ____PVOP_ALT_CALL(PVOP_RETVAL(rettype), op.func, alt, cond, \
+ CLBR_RET_REG, PVOP_CALLEE_CLOBBERS, , ##__VA_ARGS__)
+
+
#define __PVOP_VCALL(op, ...) \
(void)____PVOP_CALL(, op, CLBR_ANY, PVOP_VCALL_CLOBBERS, \
VEXTRA_CLOBBERS, ##__VA_ARGS__)
+#define __PVOP_ALT_VCALL(op, alt, cond, ...) \
+ (void)____PVOP_ALT_CALL(, op, alt, cond, CLBR_ANY, \
+ PVOP_VCALL_CLOBBERS, VEXTRA_CLOBBERS, \
+ ##__VA_ARGS__)
+
#define __PVOP_VCALLEESAVE(op, ...) \
(void)____PVOP_CALL(, op.func, CLBR_RET_REG, \
- PVOP_VCALLEE_CLOBBERS, , ##__VA_ARGS__)
+ PVOP_VCALLEE_CLOBBERS, , ##__VA_ARGS__)
+#define __PVOP_ALT_VCALLEESAVE(op, alt, cond, ...) \
+ (void)____PVOP_ALT_CALL(, op.func, alt, cond, CLBR_RET_REG, \
+ PVOP_VCALLEE_CLOBBERS, , ##__VA_ARGS__)
#define PVOP_CALL0(rettype, op) \
__PVOP_CALL(rettype, op)
#define PVOP_VCALL0(op) \
__PVOP_VCALL(op)
+#define PVOP_ALT_CALL0(rettype, op, alt, cond) \
+ __PVOP_ALT_CALL(rettype, op, alt, cond)
+#define PVOP_ALT_VCALL0(op, alt, cond) \
+ __PVOP_ALT_VCALL(op, alt, cond)
#define PVOP_CALLEE0(rettype, op) \
__PVOP_CALLEESAVE(rettype, op)
#define PVOP_VCALLEE0(op) \
__PVOP_VCALLEESAVE(op)
+#define PVOP_ALT_CALLEE0(rettype, op, alt, cond) \
+ __PVOP_ALT_CALLEESAVE(rettype, op, alt, cond)
+#define PVOP_ALT_VCALLEE0(op, alt, cond) \
+ __PVOP_ALT_VCALLEESAVE(op, alt, cond)
#define PVOP_CALL1(rettype, op, arg1) \
__PVOP_CALL(rettype, op, PVOP_CALL_ARG1(arg1))
#define PVOP_VCALL1(op, arg1) \
__PVOP_VCALL(op, PVOP_CALL_ARG1(arg1))
+#define PVOP_ALT_VCALL1(op, arg1, alt, cond) \
+ __PVOP_ALT_VCALL(op, alt, cond, PVOP_CALL_ARG1(arg1))
#define PVOP_CALLEE1(rettype, op, arg1) \
__PVOP_CALLEESAVE(rettype, op, PVOP_CALL_ARG1(arg1))
#define PVOP_VCALLEE1(op, arg1) \
__PVOP_VCALLEESAVE(op, PVOP_CALL_ARG1(arg1))
+#define PVOP_ALT_CALLEE1(rettype, op, arg1, alt, cond) \
+ __PVOP_ALT_CALLEESAVE(rettype, op, alt, cond, PVOP_CALL_ARG1(arg1))
+#define PVOP_ALT_VCALLEE1(op, arg1, alt, cond) \
+ __PVOP_ALT_VCALLEESAVE(op, alt, cond, PVOP_CALL_ARG1(arg1))
#define PVOP_CALL2(rettype, op, arg1, arg2) \
--
2.26.2
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^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v4 14/15] x86/paravirt: switch functions with custom code to ALTERNATIVE
2021-01-20 13:25 [PATCH v4 00/15] x86: major paravirt cleanup Juergen Gross via Virtualization
` (8 preceding siblings ...)
2021-01-20 13:26 ` [PATCH v4 13/15] x86/paravirt: add new macros PVOP_ALT* supporting pvops in ALTERNATIVEs Juergen Gross via Virtualization
@ 2021-01-20 13:26 ` Juergen Gross via Virtualization
2021-01-20 13:26 ` [PATCH v4 15/15] x86/paravirt: have only one paravirt patch function Juergen Gross via Virtualization
10 siblings, 0 replies; 15+ messages in thread
From: Juergen Gross via Virtualization @ 2021-01-20 13:26 UTC (permalink / raw)
To: bpetkov, x86, linux-kernel, virtualization
Instead of using paravirt patching for custom code sequences use
ALTERNATIVE for the functions with custom code replacements.
Instead of patching an ud2 instruction for unpopulated vector entries
into the caller site, use a simple function just calling BUG() as a
replacement.
Simplify the register defines for assembler paravirt calling, as there
isn't much usage left.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V4:
- fixed SAVE_FLAGS() (kernel test robot)
- added assembler paravirt cleanup
---
arch/x86/entry/entry_64.S | 2 +-
arch/x86/include/asm/irqflags.h | 2 +-
arch/x86/include/asm/paravirt.h | 99 +++++++++++++--------------
arch/x86/include/asm/paravirt_types.h | 6 --
arch/x86/kernel/paravirt.c | 16 ++---
arch/x86/kernel/paravirt_patch.c | 88 ------------------------
6 files changed, 56 insertions(+), 157 deletions(-)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index ce0464d630a2..714af508fe30 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -305,7 +305,7 @@ SYM_CODE_END(ret_from_fork)
.macro DEBUG_ENTRY_ASSERT_IRQS_OFF
#ifdef CONFIG_DEBUG_ENTRY
pushq %rax
- SAVE_FLAGS(CLBR_RAX)
+ SAVE_FLAGS
testl $X86_EFLAGS_IF, %eax
jz .Lokay_\@
ud2
diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index a0efbcd24b86..c5ce9845c999 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -111,7 +111,7 @@ static __always_inline unsigned long arch_local_irq_save(void)
#ifdef CONFIG_X86_64
#ifdef CONFIG_DEBUG_ENTRY
-#define SAVE_FLAGS(x) pushfq; popq %rax
+#define SAVE_FLAGS pushfq; popq %rax
#endif
#define INTERRUPT_RETURN jmp native_iret
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 36cd71fa097f..04b3067f31b5 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -137,7 +137,8 @@ static inline void write_cr0(unsigned long x)
static inline unsigned long read_cr2(void)
{
- return PVOP_CALLEE0(unsigned long, mmu.read_cr2);
+ return PVOP_ALT_CALLEE0(unsigned long, mmu.read_cr2,
+ "mov %%cr2, %%rax;", ~X86_FEATURE_XENPV);
}
static inline void write_cr2(unsigned long x)
@@ -147,12 +148,14 @@ static inline void write_cr2(unsigned long x)
static inline unsigned long __read_cr3(void)
{
- return PVOP_CALL0(unsigned long, mmu.read_cr3);
+ return PVOP_ALT_CALL0(unsigned long, mmu.read_cr3,
+ "mov %%cr3, %%rax;", ~X86_FEATURE_XENPV);
}
static inline void write_cr3(unsigned long x)
{
- PVOP_VCALL1(mmu.write_cr3, x);
+ PVOP_ALT_VCALL1(mmu.write_cr3, x,
+ "mov %%rdi, %%cr3", ~X86_FEATURE_XENPV);
}
static inline void __write_cr4(unsigned long x)
@@ -172,7 +175,7 @@ static inline void halt(void)
static inline void wbinvd(void)
{
- PVOP_VCALL0(cpu.wbinvd);
+ PVOP_ALT_VCALL0(cpu.wbinvd, "wbinvd", ~X86_FEATURE_XENPV);
}
static inline u64 paravirt_read_msr(unsigned msr)
@@ -386,22 +389,28 @@ static inline void paravirt_release_p4d(unsigned long pfn)
static inline pte_t __pte(pteval_t val)
{
- return (pte_t) { PVOP_CALLEE1(pteval_t, mmu.make_pte, val) };
+ return (pte_t) { PVOP_ALT_CALLEE1(pteval_t, mmu.make_pte, val,
+ "mov %%rdi, %%rax",
+ ~X86_FEATURE_XENPV) };
}
static inline pteval_t pte_val(pte_t pte)
{
- return PVOP_CALLEE1(pteval_t, mmu.pte_val, pte.pte);
+ return PVOP_ALT_CALLEE1(pteval_t, mmu.pte_val, pte.pte,
+ "mov %%rdi, %%rax", ~X86_FEATURE_XENPV);
}
static inline pgd_t __pgd(pgdval_t val)
{
- return (pgd_t) { PVOP_CALLEE1(pgdval_t, mmu.make_pgd, val) };
+ return (pgd_t) { PVOP_ALT_CALLEE1(pgdval_t, mmu.make_pgd, val,
+ "mov %%rdi, %%rax",
+ ~X86_FEATURE_XENPV) };
}
static inline pgdval_t pgd_val(pgd_t pgd)
{
- return PVOP_CALLEE1(pgdval_t, mmu.pgd_val, pgd.pgd);
+ return PVOP_ALT_CALLEE1(pgdval_t, mmu.pgd_val, pgd.pgd,
+ "mov %%rdi, %%rax", ~X86_FEATURE_XENPV);
}
#define __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
@@ -434,12 +443,15 @@ static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)
static inline pmd_t __pmd(pmdval_t val)
{
- return (pmd_t) { PVOP_CALLEE1(pmdval_t, mmu.make_pmd, val) };
+ return (pmd_t) { PVOP_ALT_CALLEE1(pmdval_t, mmu.make_pmd, val,
+ "mov %%rdi, %%rax",
+ ~X86_FEATURE_XENPV) };
}
static inline pmdval_t pmd_val(pmd_t pmd)
{
- return PVOP_CALLEE1(pmdval_t, mmu.pmd_val, pmd.pmd);
+ return PVOP_ALT_CALLEE1(pmdval_t, mmu.pmd_val, pmd.pmd,
+ "mov %%rdi, %%rax", ~X86_FEATURE_XENPV);
}
static inline void set_pud(pud_t *pudp, pud_t pud)
@@ -451,14 +463,16 @@ static inline pud_t __pud(pudval_t val)
{
pudval_t ret;
- ret = PVOP_CALLEE1(pudval_t, mmu.make_pud, val);
+ ret = PVOP_ALT_CALLEE1(pudval_t, mmu.make_pud, val,
+ "mov %%rdi, %%rax", ~X86_FEATURE_XENPV);
return (pud_t) { ret };
}
static inline pudval_t pud_val(pud_t pud)
{
- return PVOP_CALLEE1(pudval_t, mmu.pud_val, pud.pud);
+ return PVOP_ALT_CALLEE1(pudval_t, mmu.pud_val, pud.pud,
+ "mov %%rdi, %%rax", ~X86_FEATURE_XENPV);
}
static inline void pud_clear(pud_t *pudp)
@@ -477,14 +491,16 @@ static inline void set_p4d(p4d_t *p4dp, p4d_t p4d)
static inline p4d_t __p4d(p4dval_t val)
{
- p4dval_t ret = PVOP_CALLEE1(p4dval_t, mmu.make_p4d, val);
+ p4dval_t ret = PVOP_ALT_CALLEE1(p4dval_t, mmu.make_p4d, val,
+ "mov %%rdi, %%rax", ~X86_FEATURE_XENPV);
return (p4d_t) { ret };
}
static inline p4dval_t p4d_val(p4d_t p4d)
{
- return PVOP_CALLEE1(p4dval_t, mmu.p4d_val, p4d.p4d);
+ return PVOP_ALT_CALLEE1(p4dval_t, mmu.p4d_val, p4d.p4d,
+ "mov %%rdi, %%rax", ~X86_FEATURE_XENPV);
}
static inline void __set_pgd(pgd_t *pgdp, pgd_t pgd)
@@ -571,7 +587,9 @@ static __always_inline void pv_queued_spin_lock_slowpath(struct qspinlock *lock,
static __always_inline void pv_queued_spin_unlock(struct qspinlock *lock)
{
- PVOP_VCALLEE1(lock.queued_spin_unlock, lock);
+ PVOP_ALT_VCALLEE1(lock.queued_spin_unlock, lock,
+ "movb $0, (%%" _ASM_ARG1 ");",
+ ~X86_FEATURE_PVUNLOCK);
}
static __always_inline void pv_wait(u8 *ptr, u8 val)
@@ -586,7 +604,9 @@ static __always_inline void pv_kick(int cpu)
static __always_inline bool pv_vcpu_is_preempted(long cpu)
{
- return PVOP_CALLEE1(bool, lock.vcpu_is_preempted, cpu);
+ return PVOP_ALT_CALLEE1(bool, lock.vcpu_is_preempted, cpu,
+ "xor %%" _ASM_AX ", %%" _ASM_AX ";",
+ ~X86_FEATURE_VCPUPREEMPT);
}
void __raw_callee_save___native_queued_spin_unlock(struct qspinlock *lock);
@@ -660,17 +680,18 @@ bool __raw_callee_save___native_vcpu_is_preempted(long cpu);
#ifdef CONFIG_PARAVIRT_XXL
static inline notrace unsigned long arch_local_save_flags(void)
{
- return PVOP_CALLEE0(unsigned long, irq.save_fl);
+ return PVOP_ALT_CALLEE0(unsigned long, irq.save_fl,
+ "pushf; pop %%rax;", ~X86_FEATURE_XENPV);
}
static inline notrace void arch_local_irq_disable(void)
{
- PVOP_VCALLEE0(irq.irq_disable);
+ PVOP_ALT_VCALLEE0(irq.irq_disable, "cli;", ~X86_FEATURE_XENPV);
}
static inline notrace void arch_local_irq_enable(void)
{
- PVOP_VCALLEE0(irq.irq_enable);
+ PVOP_ALT_VCALLEE0(irq.irq_enable, "sti;", ~X86_FEATURE_XENPV);
}
static inline notrace unsigned long arch_local_irq_save(void)
@@ -715,35 +736,9 @@ extern void default_banner(void);
.popsection
-#define COND_PUSH(set, mask, reg) \
- .if ((~(set)) & mask); push %reg; .endif
-#define COND_POP(set, mask, reg) \
- .if ((~(set)) & mask); pop %reg; .endif
-
#ifdef CONFIG_X86_64
#ifdef CONFIG_PARAVIRT_XXL
-#define PV_SAVE_REGS(set) \
- COND_PUSH(set, CLBR_RAX, rax); \
- COND_PUSH(set, CLBR_RCX, rcx); \
- COND_PUSH(set, CLBR_RDX, rdx); \
- COND_PUSH(set, CLBR_RSI, rsi); \
- COND_PUSH(set, CLBR_RDI, rdi); \
- COND_PUSH(set, CLBR_R8, r8); \
- COND_PUSH(set, CLBR_R9, r9); \
- COND_PUSH(set, CLBR_R10, r10); \
- COND_PUSH(set, CLBR_R11, r11)
-#define PV_RESTORE_REGS(set) \
- COND_POP(set, CLBR_R11, r11); \
- COND_POP(set, CLBR_R10, r10); \
- COND_POP(set, CLBR_R9, r9); \
- COND_POP(set, CLBR_R8, r8); \
- COND_POP(set, CLBR_RDI, rdi); \
- COND_POP(set, CLBR_RSI, rsi); \
- COND_POP(set, CLBR_RDX, rdx); \
- COND_POP(set, CLBR_RCX, rcx); \
- COND_POP(set, CLBR_RAX, rax)
-
#define PARA_PATCH(off) ((off) / 8)
#define PARA_SITE(ptype, ops) _PVSITE(ptype, ops, .quad, 8)
#define PARA_INDIRECT(addr) *addr(%rip)
@@ -754,12 +749,14 @@ extern void default_banner(void);
X86_FEATURE_XENPV, "jmp xen_iret;", "jmp native_iret;")
#ifdef CONFIG_DEBUG_ENTRY
-#define SAVE_FLAGS(clobbers) \
- PARA_SITE(PARA_PATCH(PV_IRQ_save_fl), \
- PV_SAVE_REGS(clobbers | CLBR_CALLEE_SAVE); \
- ANNOTATE_RETPOLINE_SAFE; \
- call PARA_INDIRECT(pv_ops+PV_IRQ_save_fl); \
- PV_RESTORE_REGS(clobbers | CLBR_CALLEE_SAVE);)
+.macro PARA_IRQ_save_fl
+ PARA_SITE(PARA_PATCH(PV_IRQ_save_fl),
+ ANNOTATE_RETPOLINE_SAFE;
+ call PARA_INDIRECT(pv_ops+PV_IRQ_save_fl);)
+.endm
+
+#define SAVE_FLAGS ALTERNATIVE "PARA_IRQ_save_fl;", "pushf; pop %rax;", \
+ ~X86_FEATURE_XENPV
#endif
#endif /* CONFIG_PARAVIRT_XXL */
#endif /* CONFIG_X86_64 */
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 0ed976286d49..588ff14ce969 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -3,7 +3,6 @@
#define _ASM_X86_PARAVIRT_TYPES_H
/* Bitmask of what can be clobbered: usually at least eax. */
-#define CLBR_NONE 0
#define CLBR_EAX (1 << 0)
#define CLBR_ECX (1 << 1)
#define CLBR_EDX (1 << 2)
@@ -15,7 +14,6 @@
#define CLBR_ARG_REGS (CLBR_EAX | CLBR_EDX | CLBR_ECX)
#define CLBR_RET_REG (CLBR_EAX | CLBR_EDX)
-#define CLBR_SCRATCH (0)
#else
#define CLBR_RAX CLBR_EAX
#define CLBR_RCX CLBR_ECX
@@ -32,12 +30,9 @@
#define CLBR_ARG_REGS (CLBR_RDI | CLBR_RSI | CLBR_RDX | \
CLBR_RCX | CLBR_R8 | CLBR_R9)
#define CLBR_RET_REG (CLBR_RAX)
-#define CLBR_SCRATCH (CLBR_R10 | CLBR_R11)
#endif /* X86_64 */
-#define CLBR_CALLEE_SAVE ((CLBR_ARG_REGS | CLBR_SCRATCH) & ~CLBR_RET_REG)
-
#ifndef __ASSEMBLY__
#include <asm/desc_defs.h>
@@ -322,7 +317,6 @@ extern void (*paravirt_iret)(void);
/* Simple instruction patching code. */
#define NATIVE_LABEL(a,x,b) "\n\t.globl " a #x "_" #b "\n" a #x "_" #b ":\n\t"
-unsigned paravirt_patch_ident_64(void *insn_buff, unsigned len);
unsigned paravirt_patch_default(u8 type, void *insn_buff, unsigned long addr, unsigned len);
unsigned paravirt_patch_insns(void *insn_buff, unsigned len, const char *start, const char *end);
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 0553a339d850..082954930809 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -53,7 +53,10 @@ void __init default_banner(void)
}
/* Undefined instruction for dealing with missing ops pointers. */
-static const unsigned char ud2a[] = { 0x0f, 0x0b };
+static void paravirt_BUG(void)
+{
+ BUG();
+}
struct branch {
unsigned char opcode;
@@ -107,17 +110,10 @@ unsigned paravirt_patch_default(u8 type, void *insn_buff,
unsigned ret;
if (opfunc == NULL)
- /* If there's no function, patch it with a ud2a (BUG) */
- ret = paravirt_patch_insns(insn_buff, len, ud2a, ud2a+sizeof(ud2a));
+ /* If there's no function, patch it with paravirt_BUG() */
+ ret = paravirt_patch_call(insn_buff, paravirt_BUG, addr, len);
else if (opfunc == _paravirt_nop)
ret = 0;
-
-#ifdef CONFIG_PARAVIRT_XXL
- /* identity functions just return their single argument */
- else if (opfunc == _paravirt_ident_64)
- ret = paravirt_patch_ident_64(insn_buff, len);
-
-#endif
else
/* Otherwise call the function. */
ret = paravirt_patch_call(insn_buff, opfunc, addr, len);
diff --git a/arch/x86/kernel/paravirt_patch.c b/arch/x86/kernel/paravirt_patch.c
index abd27ec67397..10543dcc8211 100644
--- a/arch/x86/kernel/paravirt_patch.c
+++ b/arch/x86/kernel/paravirt_patch.c
@@ -4,96 +4,8 @@
#include <asm/paravirt.h>
#include <asm/asm-offsets.h>
-#define PSTART(d, m) \
- patch_data_##d.m
-
-#define PEND(d, m) \
- (PSTART(d, m) + sizeof(patch_data_##d.m))
-
-#define PATCH(d, m, insn_buff, len) \
- paravirt_patch_insns(insn_buff, len, PSTART(d, m), PEND(d, m))
-
-#define PATCH_CASE(ops, m, data, insn_buff, len) \
- case PARAVIRT_PATCH(ops.m): \
- return PATCH(data, ops##_##m, insn_buff, len)
-
-#ifdef CONFIG_PARAVIRT_XXL
-struct patch_xxl {
- const unsigned char irq_irq_disable[1];
- const unsigned char irq_irq_enable[1];
- const unsigned char irq_save_fl[2];
- const unsigned char mmu_read_cr2[3];
- const unsigned char mmu_read_cr3[3];
- const unsigned char mmu_write_cr3[3];
- const unsigned char cpu_wbinvd[2];
- const unsigned char mov64[3];
-};
-
-static const struct patch_xxl patch_data_xxl = {
- .irq_irq_disable = { 0xfa }, // cli
- .irq_irq_enable = { 0xfb }, // sti
- .irq_save_fl = { 0x9c, 0x58 }, // pushf; pop %[re]ax
- .mmu_read_cr2 = { 0x0f, 0x20, 0xd0 }, // mov %cr2, %[re]ax
- .mmu_read_cr3 = { 0x0f, 0x20, 0xd8 }, // mov %cr3, %[re]ax
- .mmu_write_cr3 = { 0x0f, 0x22, 0xdf }, // mov %rdi, %cr3
- .cpu_wbinvd = { 0x0f, 0x09 }, // wbinvd
- .mov64 = { 0x48, 0x89, 0xf8 }, // mov %rdi, %rax
-};
-
-unsigned int paravirt_patch_ident_64(void *insn_buff, unsigned int len)
-{
- return PATCH(xxl, mov64, insn_buff, len);
-}
-# endif /* CONFIG_PARAVIRT_XXL */
-
-#ifdef CONFIG_PARAVIRT_SPINLOCKS
-struct patch_lock {
- unsigned char queued_spin_unlock[3];
- unsigned char vcpu_is_preempted[2];
-};
-
-static const struct patch_lock patch_data_lock = {
- .vcpu_is_preempted = { 0x31, 0xc0 }, // xor %eax, %eax
-
-# ifdef CONFIG_X86_64
- .queued_spin_unlock = { 0xc6, 0x07, 0x00 }, // movb $0, (%rdi)
-# else
- .queued_spin_unlock = { 0xc6, 0x00, 0x00 }, // movb $0, (%eax)
-# endif
-};
-#endif /* CONFIG_PARAVIRT_SPINLOCKS */
-
unsigned int native_patch(u8 type, void *insn_buff, unsigned long addr,
unsigned int len)
{
- switch (type) {
-
-#ifdef CONFIG_PARAVIRT_XXL
- PATCH_CASE(irq, save_fl, xxl, insn_buff, len);
- PATCH_CASE(irq, irq_enable, xxl, insn_buff, len);
- PATCH_CASE(irq, irq_disable, xxl, insn_buff, len);
-
- PATCH_CASE(mmu, read_cr2, xxl, insn_buff, len);
- PATCH_CASE(mmu, read_cr3, xxl, insn_buff, len);
- PATCH_CASE(mmu, write_cr3, xxl, insn_buff, len);
-
- PATCH_CASE(cpu, wbinvd, xxl, insn_buff, len);
-#endif
-
-#ifdef CONFIG_PARAVIRT_SPINLOCKS
- case PARAVIRT_PATCH(lock.queued_spin_unlock):
- if (pv_is_native_spin_unlock())
- return PATCH(lock, queued_spin_unlock, insn_buff, len);
- break;
-
- case PARAVIRT_PATCH(lock.vcpu_is_preempted):
- if (pv_is_native_vcpu_is_preempted())
- return PATCH(lock, vcpu_is_preempted, insn_buff, len);
- break;
-#endif
- default:
- break;
- }
-
return paravirt_patch_default(type, insn_buff, addr, len);
}
--
2.26.2
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^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v4 15/15] x86/paravirt: have only one paravirt patch function
2021-01-20 13:25 [PATCH v4 00/15] x86: major paravirt cleanup Juergen Gross via Virtualization
` (9 preceding siblings ...)
2021-01-20 13:26 ` [PATCH v4 14/15] x86/paravirt: switch functions with custom code to ALTERNATIVE Juergen Gross via Virtualization
@ 2021-01-20 13:26 ` Juergen Gross via Virtualization
10 siblings, 0 replies; 15+ messages in thread
From: Juergen Gross via Virtualization @ 2021-01-20 13:26 UTC (permalink / raw)
To: bpetkov, x86, virtualization, linux-kernel
There is no need any longer to have different paravirt patch functions
for native and Xen. Eliminate native_patch() and rename
paravirt_patch_default() to paravirt_patch().
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V3:
- remove paravirt_patch_insns() (kernel test robot)
---
arch/x86/include/asm/paravirt_types.h | 19 +------------------
arch/x86/kernel/Makefile | 3 +--
arch/x86/kernel/alternative.c | 2 +-
arch/x86/kernel/paravirt.c | 20 ++------------------
arch/x86/kernel/paravirt_patch.c | 11 -----------
arch/x86/xen/enlighten_pv.c | 1 -
6 files changed, 5 insertions(+), 51 deletions(-)
delete mode 100644 arch/x86/kernel/paravirt_patch.c
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 588ff14ce969..62efbf8bd8f0 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -68,19 +68,6 @@ struct pv_info {
const char *name;
};
-struct pv_init_ops {
- /*
- * Patch may replace one of the defined code sequences with
- * arbitrary code, subject to the same register constraints.
- * This generally means the code is not free to clobber any
- * registers other than EAX. The patch function should return
- * the number of bytes of code generated, as we nop pad the
- * rest in generic code.
- */
- unsigned (*patch)(u8 type, void *insn_buff,
- unsigned long addr, unsigned len);
-} __no_randomize_layout;
-
#ifdef CONFIG_PARAVIRT_XXL
struct pv_lazy_ops {
/* Set deferred update mode, used for batching operations. */
@@ -276,7 +263,6 @@ struct pv_lock_ops {
* number for each function using the offset which we use to indicate
* what to patch. */
struct paravirt_patch_template {
- struct pv_init_ops init;
struct pv_cpu_ops cpu;
struct pv_irq_ops irq;
struct pv_mmu_ops mmu;
@@ -317,10 +303,7 @@ extern void (*paravirt_iret)(void);
/* Simple instruction patching code. */
#define NATIVE_LABEL(a,x,b) "\n\t.globl " a #x "_" #b "\n" a #x "_" #b ":\n\t"
-unsigned paravirt_patch_default(u8 type, void *insn_buff, unsigned long addr, unsigned len);
-unsigned paravirt_patch_insns(void *insn_buff, unsigned len, const char *start, const char *end);
-
-unsigned native_patch(u8 type, void *insn_buff, unsigned long addr, unsigned len);
+unsigned paravirt_patch(u8 type, void *insn_buff, unsigned long addr, unsigned len);
int paravirt_disable_iospace(void);
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 5eeb808eb024..853a83503120 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -35,7 +35,6 @@ KASAN_SANITIZE_sev-es.o := n
KCSAN_SANITIZE := n
OBJECT_FILES_NON_STANDARD_test_nx.o := y
-OBJECT_FILES_NON_STANDARD_paravirt_patch.o := y
ifdef CONFIG_FRAME_POINTER
OBJECT_FILES_NON_STANDARD_ftrace_$(BITS).o := y
@@ -122,7 +121,7 @@ obj-$(CONFIG_AMD_NB) += amd_nb.o
obj-$(CONFIG_DEBUG_NMI_SELFTEST) += nmi_selftest.o
obj-$(CONFIG_KVM_GUEST) += kvm.o kvmclock.o
-obj-$(CONFIG_PARAVIRT) += paravirt.o paravirt_patch.o
+obj-$(CONFIG_PARAVIRT) += paravirt.o
obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= paravirt-spinlocks.o
obj-$(CONFIG_PARAVIRT_CLOCK) += pvclock.o
obj-$(CONFIG_X86_PMEM_LEGACY_DEVICE) += pmem.o
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 221acb2b868a..fb0b83c85de7 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -613,7 +613,7 @@ void __init_or_module apply_paravirt(struct paravirt_patch_site *start,
BUG_ON(p->len > MAX_PATCH_LEN);
/* prep the buffer with the original instructions */
memcpy(insn_buff, p->instr, p->len);
- used = pv_ops.init.patch(p->type, insn_buff, (unsigned long)p->instr, p->len);
+ used = paravirt_patch(p->type, insn_buff, (unsigned long)p->instr, p->len);
BUG_ON(used > p->len);
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 082954930809..3d7b989ed6be 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -99,8 +99,8 @@ void __init native_pv_lock_init(void)
static_branch_disable(&virt_spin_lock_key);
}
-unsigned paravirt_patch_default(u8 type, void *insn_buff,
- unsigned long addr, unsigned len)
+unsigned int paravirt_patch(u8 type, void *insn_buff, unsigned long addr,
+ unsigned int len)
{
/*
* Neat trick to map patch type back to the call within the
@@ -121,19 +121,6 @@ unsigned paravirt_patch_default(u8 type, void *insn_buff,
return ret;
}
-unsigned paravirt_patch_insns(void *insn_buff, unsigned len,
- const char *start, const char *end)
-{
- unsigned insn_len = end - start;
-
- /* Alternative instruction is too large for the patch site and we cannot continue: */
- BUG_ON(insn_len > len || start == NULL);
-
- memcpy(insn_buff, start, insn_len);
-
- return insn_len;
-}
-
struct static_key paravirt_steal_enabled;
struct static_key paravirt_steal_rq_enabled;
@@ -255,9 +242,6 @@ struct pv_info pv_info = {
#define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
struct paravirt_patch_template pv_ops = {
- /* Init ops. */
- .init.patch = native_patch,
-
/* Cpu ops. */
.cpu.io_delay = native_io_delay,
diff --git a/arch/x86/kernel/paravirt_patch.c b/arch/x86/kernel/paravirt_patch.c
deleted file mode 100644
index 10543dcc8211..000000000000
--- a/arch/x86/kernel/paravirt_patch.c
+++ /dev/null
@@ -1,11 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include <linux/stringify.h>
-
-#include <asm/paravirt.h>
-#include <asm/asm-offsets.h>
-
-unsigned int native_patch(u8 type, void *insn_buff, unsigned long addr,
- unsigned int len)
-{
- return paravirt_patch_default(type, insn_buff, addr, len);
-}
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 4716383c64a9..66f83de4d9e0 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -1218,7 +1218,6 @@ asmlinkage __visible void __init xen_start_kernel(void)
/* Install Xen paravirt ops */
pv_info = xen_info;
- pv_ops.init.patch = paravirt_patch_default;
pv_ops.cpu = xen_cpu_ops;
paravirt_iret = xen_iret;
xen_init_irq_ops();
--
2.26.2
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^ permalink raw reply related [flat|nested] 15+ messages in thread