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Message-ID: <20121022201451.GJ25200@phenom.dumpdata.com>
Date: Mon, 22 Oct 2012 16:14:51 -0400
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To: Mukesh Rathor <mukesh.rathor@...cle.com>
Cc: Stefano Stabellini <stefano.stabellini@...citrix.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"xen-devel@...ts.xensource.com" <xen-devel@...ts.xensource.com>,
Ian Campbell <Ian.Campbell@...rix.com>
Subject: Re: [PATCH 2/6] xen/pvh: Extend vcpu_guest_context, p2m, event, and
xenbus to support PVH.
On Mon, Oct 22, 2012 at 11:31:54AM -0700, Mukesh Rathor wrote:
> On Mon, 22 Oct 2012 14:44:40 +0100
> Stefano Stabellini <stefano.stabellini@...citrix.com> wrote:
>
> > On Sat, 20 Oct 2012, Konrad Rzeszutek Wilk wrote:
> > > From: Mukesh Rathor <mukesh.rathor@...cle.com>
> > >
> > > make gdt_frames[]/gdt_ents into a union with {gdtaddr, gdtsz}, as
> > > PVH only needs to send down gdtaddr and gdtsz.
> > >
> > > For interrupts, PVH uses native_irq_ops.
> > > vcpu hotplug is currently not available for PVH.
> > >
> > > For events we follow what PVHVM does - to use callback vector.
> > > Lastly, also use HVM path to setup XenBus.
> > >
> > > Signed-off-by: Mukesh Rathor <mukesh.rathor@...cle.com>
> > > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> > > ---
> > > return true;
> > > }
> > > - xen_copy_trap_info(ctxt->trap_ctxt);
> > > + /* check for autoxlated to get it right for 32bit kernel */
> >
> > I am not sure what this comment means, considering that in another
> > comment below you say that we don't support 32bit PVH kernels.
>
> Function is common to both 32bit and 64bit kernels. We need to check
> for auto xlated also in the if statement in addition to supervisor
> mode kernel, so 32 bit doesn't go down the wrong path.
Can one just make it #ifdef CONFIG_X86_64 for the whole thing?
You are either way during bootup doing a 'BUG' when booting as 32-bit?
>
> PVH is not supported for 32bit kernels, and gs_base_user doesn't exist
> in the structure for 32bit so it needs to be if'def'd 64bit which is
> ok because PVH is not supprted on 32bit kernel.
>
> > > + (unsigned
> > > long)xen_hypervisor_callback;
> > > + ctxt->failsafe_callback_eip =
> > > + (unsigned
> > > long)xen_failsafe_callback;
> > > + }
> > > + ctxt->user_regs.cs = __KERNEL_CS;
> > > + ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct
> > > pt_regs);
> > > per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
> > > ctxt->ctrlreg[3] =
> > > xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
> >
> > The tradional path looks the same as before, however it is hard to
> > tell whether the PVH path is correct without the Xen side. For
> > example, what is gdtsz?
>
> gdtsz is GUEST_GDTR_LIMIT and gdtaddr is GUEST_GDTR_BASE in the vmcs.
looking at this I figured it could be a bit neater. So I split it in
two patches which should make it easier to read the PVH one.
>From f9455e293169d73e5698df62801bcd5fd64a5259 Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Date: Mon, 22 Oct 2012 11:35:16 -0400
Subject: [PATCH 1/2] xen/smp: Move the common CPU init code a bit to prep for
PVH patch.
The PV and PVH code CPU init code share some functionality. The
PVH code ("xen/pvh: Extend vcpu_guest_context, p2m, event, and XenBus")
sets some of these up, but not all. To make it easier to read, this
patch removes the PV specific out of the generic way.
No functional change, just code move.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
---
arch/x86/xen/smp.c | 42 +++++++++++++++++++++++-------------------
1 files changed, 23 insertions(+), 19 deletions(-)
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 353c50f..ba49a3a 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -300,8 +300,6 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
gdt = get_cpu_gdt_table(cpu);
ctxt->flags = VGCF_IN_KERNEL;
- ctxt->user_regs.ds = __USER_DS;
- ctxt->user_regs.es = __USER_DS;
ctxt->user_regs.ss = __KERNEL_DS;
#ifdef CONFIG_X86_32
ctxt->user_regs.fs = __KERNEL_PERCPU;
@@ -310,35 +308,41 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
ctxt->gs_base_kernel = per_cpu_offset(cpu);
#endif
ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle;
- ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
- xen_copy_trap_info(ctxt->trap_ctxt);
+ {
+ ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
+ ctxt->user_regs.ds = __USER_DS;
+ ctxt->user_regs.es = __USER_DS;
- ctxt->ldt_ents = 0;
+ xen_copy_trap_info(ctxt->trap_ctxt);
- BUG_ON((unsigned long)gdt & ~PAGE_MASK);
+ ctxt->ldt_ents = 0;
- gdt_mfn = arbitrary_virt_to_mfn(gdt);
- make_lowmem_page_readonly(gdt);
- make_lowmem_page_readonly(mfn_to_virt(gdt_mfn));
+ BUG_ON((unsigned long)gdt & ~PAGE_MASK);
- ctxt->gdt_frames[0] = gdt_mfn;
- ctxt->gdt_ents = GDT_ENTRIES;
+ gdt_mfn = arbitrary_virt_to_mfn(gdt);
+ make_lowmem_page_readonly(gdt);
+ make_lowmem_page_readonly(mfn_to_virt(gdt_mfn));
- ctxt->user_regs.cs = __KERNEL_CS;
- ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs);
+ ctxt->u.pv.gdt_frames[0] = gdt_mfn;
+ ctxt->u.pv.gdt_ents = GDT_ENTRIES;
- ctxt->kernel_ss = __KERNEL_DS;
- ctxt->kernel_sp = idle->thread.sp0;
+ ctxt->kernel_ss = __KERNEL_DS;
+ ctxt->kernel_sp = idle->thread.sp0;
#ifdef CONFIG_X86_32
- ctxt->event_callback_cs = __KERNEL_CS;
- ctxt->failsafe_callback_cs = __KERNEL_CS;
+ ctxt->event_callback_cs = __KERNEL_CS;
+ ctxt->failsafe_callback_cs = __KERNEL_CS;
#endif
- ctxt->event_callback_eip = (unsigned long)xen_hypervisor_callback;
- ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback;
+ ctxt->event_callback_eip =
+ (unsigned long)xen_hypervisor_callback;
+ ctxt->failsafe_callback_eip =
+ (unsigned long)xen_failsafe_callback;
+ }
+ ctxt->user_regs.cs = __KERNEL_CS;
+ ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs);
per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
--
1.7.7.6
>From 2c4dd7f567b229451f3dc1ae00d784da8b4a5072 Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Date: Mon, 22 Oct 2012 11:37:57 -0400
Subject: [PATCH 2/2] xen/pvh: Extend vcpu_guest_context, p2m, event, and
XenBus.
Make gdt_frames[]/gdt_ents into a union with {gdtaddr, gdtsz},
as PVH only needs to send down gdtaddr and gdtsz in the
vcpu_guest_context structure..
For interrupts, PVH uses native_irq_ops so we can skip most of the
PV ones. In the future we can support the pirq_eoi_map..
Also VCPU hotplug is currently not available for PVH.
For events (and IRQs) we follow what PVHVM does - so use callback
vector. Lastly, for XenBus we use the same logic that is used in
the PVHVM case.
Signed-off-by: Mukesh Rathor <mukesh.rathor@...cle.com>
[v2: Rebased it]
[v3: Move 64-bit ifdef and based on Stefan add extra comments.]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
---
arch/x86/include/asm/xen/interface.h | 11 +++++++++-
arch/x86/xen/irq.c | 5 +++-
arch/x86/xen/p2m.c | 2 +-
arch/x86/xen/smp.c | 36 ++++++++++++++++++++++++++-------
drivers/xen/cpu_hotplug.c | 4 ++-
drivers/xen/events.c | 9 +++++++-
drivers/xen/xenbus/xenbus_client.c | 3 +-
7 files changed, 56 insertions(+), 14 deletions(-)
diff --git a/arch/x86/include/asm/xen/interface.h b/arch/x86/include/asm/xen/interface.h
index 6d2f75a..4c08f23 100644
--- a/arch/x86/include/asm/xen/interface.h
+++ b/arch/x86/include/asm/xen/interface.h
@@ -144,7 +144,16 @@ struct vcpu_guest_context {
struct cpu_user_regs user_regs; /* User-level CPU registers */
struct trap_info trap_ctxt[256]; /* Virtual IDT */
unsigned long ldt_base, ldt_ents; /* LDT (linear address, # ents) */
- unsigned long gdt_frames[16], gdt_ents; /* GDT (machine frames, # ents) */
+ union {
+ struct {
+ /* PV: GDT (machine frames, # ents).*/
+ unsigned long gdt_frames[16], gdt_ents;
+ } pv;
+ struct {
+ /* PVH: GDTR addr and size */
+ unsigned long gdtaddr, gdtsz;
+ } pvh;
+ } u;
unsigned long kernel_ss, kernel_sp; /* Virtual TSS (only SS1/SP1) */
/* NB. User pagetable on x86/64 is placed in ctrlreg[1]. */
unsigned long ctrlreg[8]; /* CR0-CR7 (control registers) */
diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c
index 01a4dc0..fcbe56a 100644
--- a/arch/x86/xen/irq.c
+++ b/arch/x86/xen/irq.c
@@ -5,6 +5,7 @@
#include <xen/interface/xen.h>
#include <xen/interface/sched.h>
#include <xen/interface/vcpu.h>
+#include <xen/features.h>
#include <xen/events.h>
#include <asm/xen/hypercall.h>
@@ -129,6 +130,8 @@ static const struct pv_irq_ops xen_irq_ops __initconst = {
void __init xen_init_irq_ops(void)
{
- pv_irq_ops = xen_irq_ops;
+ /* For PVH we use default pv_irq_ops settings */
+ if (!xen_feature(XENFEAT_hvm_callback_vector))
+ pv_irq_ops = xen_irq_ops;
x86_init.irqs.intr_init = xen_init_IRQ;
}
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 95fb2aa..ea553c8 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -798,7 +798,7 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
{
unsigned topidx, mididx, idx;
- if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
+ if (xen_feature(XENFEAT_auto_translated_physmap)) {
BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
return true;
}
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index ba49a3a..6f831a1 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -68,9 +68,11 @@ static void __cpuinit cpu_bringup(void)
touch_softlockup_watchdog();
preempt_disable();
- xen_enable_sysenter();
- xen_enable_syscall();
-
+ /* PVH runs in ring 0 and allows us to do native syscalls. Yay! */
+ if (!xen_feature(XENFEAT_supervisor_mode_kernel)) {
+ xen_enable_sysenter();
+ xen_enable_syscall();
+ }
cpu = smp_processor_id();
smp_store_cpu_info(cpu);
cpu_data(cpu).x86_max_cores = 1;
@@ -230,10 +232,11 @@ static void __init xen_smp_prepare_boot_cpu(void)
BUG_ON(smp_processor_id() != 0);
native_smp_prepare_boot_cpu();
- /* We've switched to the "real" per-cpu gdt, so make sure the
- old memory can be recycled */
- make_lowmem_page_readwrite(xen_initial_gdt);
-
+ if (!xen_feature(XENFEAT_writable_page_tables)) {
+ /* We've switched to the "real" per-cpu gdt, so make sure the
+ * old memory can be recycled */
+ make_lowmem_page_readwrite(xen_initial_gdt);
+ }
xen_filter_cpu_maps();
xen_setup_vcpu_info_placement();
}
@@ -311,7 +314,24 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
- {
+ /* check for autoxlated to get it right for 32bit kernel */
+ if (xen_feature(XENFEAT_auto_translated_physmap) &&
+ xen_feature(XENFEAT_supervisor_mode_kernel)) {
+#ifdef CONFIG_X86_64
+ ctxt->user_regs.ds = __KERNEL_DS;
+ ctxt->user_regs.es = 0;
+ ctxt->user_regs.gs = 0;
+
+ /* GUEST_GDTR_BASE and */
+ ctxt->u.pvh.gdtaddr = (unsigned long)gdt;
+ /* GUEST_GDTR_LIMIT in the VMCS. */
+ ctxt->u.pvh.gdtsz = (unsigned long)(GDT_SIZE - 1);
+
+ /* Note: PVH is not supported on x86_32. */
+ ctxt->gs_base_user = (unsigned long)
+ per_cpu(irq_stack_union.gs_base, cpu);
+#endif
+ } else {
ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
ctxt->user_regs.ds = __USER_DS;
ctxt->user_regs.es = __USER_DS;
diff --git a/drivers/xen/cpu_hotplug.c b/drivers/xen/cpu_hotplug.c
index 4dcfced..de6bcf9 100644
--- a/drivers/xen/cpu_hotplug.c
+++ b/drivers/xen/cpu_hotplug.c
@@ -2,6 +2,7 @@
#include <xen/xen.h>
#include <xen/xenbus.h>
+#include <xen/features.h>
#include <asm/xen/hypervisor.h>
#include <asm/cpu.h>
@@ -100,7 +101,8 @@ static int __init setup_vcpu_hotplug_event(void)
static struct notifier_block xsn_cpu = {
.notifier_call = setup_cpu_watcher };
- if (!xen_pv_domain())
+ /* PVH TBD/FIXME: future work */
+ if (!xen_pv_domain() || xen_feature(XENFEAT_auto_translated_physmap))
return -ENODEV;
register_xenstore_notifier(&xsn_cpu);
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 59e10a1..7131fdd 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1774,7 +1774,7 @@ int xen_set_callback_via(uint64_t via)
}
EXPORT_SYMBOL_GPL(xen_set_callback_via);
-#ifdef CONFIG_XEN_PVHVM
+#ifdef CONFIG_X86
/* Vector callbacks are better than PCI interrupts to receive event
* channel notifications because we can receive vector callbacks on any
* vcpu and we don't need PCI support or APIC interactions. */
@@ -1835,6 +1835,13 @@ void __init xen_init_IRQ(void)
if (xen_initial_domain())
pci_xen_initial_domain();
+ if (xen_feature(XENFEAT_hvm_callback_vector)) {
+ xen_callback_vector();
+ return;
+ }
+
+ /* PVH: TBD/FIXME: debug and fix eio map to work with pvh */
+
pirq_eoi_map = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
eoi_gmfn.gmfn = virt_to_mfn(pirq_eoi_map);
rc = HYPERVISOR_physdev_op(PHYSDEVOP_pirq_eoi_gmfn_v2, &eoi_gmfn);
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index bcf3ba4..356461e 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -44,6 +44,7 @@
#include <xen/grant_table.h>
#include <xen/xenbus.h>
#include <xen/xen.h>
+#include <xen/features.h>
#include "xenbus_probe.h"
@@ -741,7 +742,7 @@ static const struct xenbus_ring_ops ring_ops_hvm = {
void __init xenbus_ring_ops_init(void)
{
- if (xen_pv_domain())
+ if (xen_pv_domain() && !xen_feature(XENFEAT_auto_translated_physmap))
ring_ops = &ring_ops_pv;
else
ring_ops = &ring_ops_hvm;
--
1.7.7.6
--
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