[PATCH] x86/build: Build VSMP support only if CONFIG_PCI is

From: Eial Czerwacki
Date: Thu Nov 01 2018 - 09:08:32 EST


vsmp dependency of pv_irq_ops removed some years ago, so now let's clean
it up from vsmp_64.c.

In short, "cap & ctl & (1 << 4)" was always returning 0, as such we can
remove all the PARAVIRT/PARAVIRT_XXL code handling that.

However, the rest of the code depends on CONFIG_PCI, so fix it accordingly.

Signed-off-by: Eial Czerwacki <eial@xxxxxxxxxxx>
Acked-by: Shai Fultheim <shai@xxxxxxxxxxx>
---
arch/x86/Kconfig | 1 -
arch/x86/kernel/vsmp_64.c | 80
+++--------------------------------------------
2 files changed, 5 insertions(+), 76 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c51c989..4b187ca 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -524,7 +524,6 @@ config X86_VSMP
bool "ScaleMP vSMP"
select HYPERVISOR_GUEST
select PARAVIRT
- select PARAVIRT_XXL
depends on X86_64 && PCI
depends on X86_EXTENDED_PLATFORM
depends on SMP
diff --git a/arch/x86/kernel/vsmp_64.c b/arch/x86/kernel/vsmp_64.c
index 1eae5af..c6d2b76 100644
--- a/arch/x86/kernel/vsmp_64.c
+++ b/arch/x86/kernel/vsmp_64.c
@@ -26,64 +26,7 @@

#define TOPOLOGY_REGISTER_OFFSET 0x10

-#if defined CONFIG_PCI && defined CONFIG_PARAVIRT_XXL
-/*
- * Interrupt control on vSMPowered systems:
- * ~AC is a shadow of IF. If IF is 'on' AC should be 'off'
- * and vice versa.
- */
-
-asmlinkage __visible unsigned long vsmp_save_fl(void)
-{
- unsigned long flags = native_save_fl();
-
- if (!(flags & X86_EFLAGS_IF) || (flags & X86_EFLAGS_AC))
- flags &= ~X86_EFLAGS_IF;
- return flags;
-}
-PV_CALLEE_SAVE_REGS_THUNK(vsmp_save_fl);
-
-__visible void vsmp_restore_fl(unsigned long flags)
-{
- if (flags & X86_EFLAGS_IF)
- flags &= ~X86_EFLAGS_AC;
- else
- flags |= X86_EFLAGS_AC;
- native_restore_fl(flags);
-}
-PV_CALLEE_SAVE_REGS_THUNK(vsmp_restore_fl);
-
-asmlinkage __visible void vsmp_irq_disable(void)
-{
- unsigned long flags = native_save_fl();
-
- native_restore_fl((flags & ~X86_EFLAGS_IF) | X86_EFLAGS_AC);
-}
-PV_CALLEE_SAVE_REGS_THUNK(vsmp_irq_disable);
-
-asmlinkage __visible void vsmp_irq_enable(void)
-{
- unsigned long flags = native_save_fl();
-
- native_restore_fl((flags | X86_EFLAGS_IF) & (~X86_EFLAGS_AC));
-}
-PV_CALLEE_SAVE_REGS_THUNK(vsmp_irq_enable);
-
-static unsigned __init vsmp_patch(u8 type, void *ibuf,
- unsigned long addr, unsigned len)
-{
- switch (type) {
- case PARAVIRT_PATCH(irq.irq_enable):
- case PARAVIRT_PATCH(irq.irq_disable):
- case PARAVIRT_PATCH(irq.save_fl):
- case PARAVIRT_PATCH(irq.restore_fl):
- return paravirt_patch_default(type, ibuf, addr, len);
- default:
- return native_patch(type, ibuf, addr, len);
- }
-
-}
-
+#if defined CONFIG_PCI
static void __init set_vsmp_pv_ops(void)
{
void __iomem *address;
@@ -109,28 +52,12 @@ static void __init set_vsmp_pv_ops(void)
}
#endif

- if (cap & ctl & (1 << 4)) {
- /* Setup irq ops and turn on vSMP IRQ fastpath handling */
- pv_ops.irq.irq_disable = PV_CALLEE_SAVE(vsmp_irq_disable);
- pv_ops.irq.irq_enable = PV_CALLEE_SAVE(vsmp_irq_enable);
- pv_ops.irq.save_fl = PV_CALLEE_SAVE(vsmp_save_fl);
- pv_ops.irq.restore_fl = PV_CALLEE_SAVE(vsmp_restore_fl);
- pv_ops.init.patch = vsmp_patch;
- ctl &= ~(1 << 4);
- }
writel(ctl, address + 4);
ctl = readl(address + 4);
pr_info("vSMP CTL: control set to:0x%08x\n", ctl);

early_iounmap(address, 8);
}
-#else
-static void __init set_vsmp_pv_ops(void)
-{
-}
-#endif
-
-#ifdef CONFIG_PCI
static int is_vsmp = -1;

static void __init detect_vsmp_box(void)
@@ -164,11 +91,14 @@ static int is_vsmp_box(void)
{
return 0;
}
+static void __init set_vsmp_pv_ops(void)
+{
+}
#endif

static void __init vsmp_cap_cpus(void)
{
-#if !defined(CONFIG_X86_VSMP) && defined(CONFIG_SMP)
+#if !defined(CONFIG_X86_VSMP) && defined(CONFIG_SMP) && defined(CONFIG_PCI)
void __iomem *address;
unsigned int cfg, topology, node_shift, maxcpus;

--
2.7.4