Re: [Xen-devel] [PATCH 2 of 5] early PV on HVM

From: Jeremy Fitzhardinge
Date: Thu Mar 11 2010 - 16:20:46 EST

On 03/10/2010 07:47 AM, Stefano Stabellini wrote:
Hi all,
this patch:

- adds a xen_guest_init hook in setup.c right after kvm_guest_init;

- initializes basic pv on hvm features in xen_guest_init;

Is this 64-bit specific like Sheng's version?

I also asked him to move the setup code out of enlighten.c into a new file, though your version is a fair bit smaller.

Signed-off-by: Stefano Stabellini<stefano.stabellini@xxxxxxxxxxxxx>
Signed-off-by: Sheng Yang<sheng@xxxxxxxxxxxxxxx>
Signed-off-by: Yaozu (Eddie) Dong<eddie.dong@xxxxxxxxx>

---

diff --git a/arch/x86/include/asm/xen/hypervisor.h b/arch/x86/include/asm/xen/hypervisor.h
index d5b7e90..bbd3f65 100644
--- a/arch/x86/include/asm/xen/hypervisor.h
+++ b/arch/x86/include/asm/xen/hypervisor.h
@@ -33,6 +33,7 @@
#ifndef _ASM_X86_XEN_HYPERVISOR_H
#define _ASM_X86_XEN_HYPERVISOR_H

+#ifdef CONFIG_XEN
/* arch/i386/kernel/setup.c */
extern struct shared_info *HYPERVISOR_shared_info;
extern struct start_info *xen_start_info;
@@ -43,10 +44,11 @@ enum xen_domain_type {
XEN_HVM_DOMAIN, /* running in a Xen hvm domain */
};

-#ifdef CONFIG_XEN
extern enum xen_domain_type xen_domain_type;
+extern void xen_guest_init(void);
#else
#define xen_domain_type XEN_NATIVE
+#define xen_guest_init() do { } while (0)
#endif

#define xen_domain() (xen_domain_type != XEN_NATIVE)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index e09f0e2..cb32e37 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -49,6 +49,7 @@
#include<asm/pci-direct.h>
#include<linux/init_ohci1394_dma.h>
#include<linux/kvm_para.h>
+#include<asm/xen/hypervisor.h>

#include<linux/errno.h>
#include<linux/kernel.h>
@@ -1007,6 +1008,7 @@ void __init setup_arch(char **cmdline_p)
probe_nr_irqs_gsi();

kvm_guest_init();
+ xen_guest_init();

e820_reserve_resources();
e820_mark_nosave_regions(max_low_pfn);
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 3439616..42135e8 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -32,6 +32,8 @@
#include<xen/interface/version.h>
#include<xen/interface/physdev.h>
#include<xen/interface/vcpu.h>
+#include<xen/interface/memory.h>
+#include<xen/interface/hvm/hvm_op.h>
#include<xen/features.h>
#include<xen/page.h>
#include<xen/hvc-console.h>
@@ -1179,3 +1181,86 @@ asmlinkage void __init xen_start_kernel(void)
x86_64_start_reservations((char *)__pa_symbol(&boot_params));
#endif
}
+
+static uint32_t xen_cpuid_base(void)
+{
+ uint32_t base, eax, ebx, ecx, edx;
+ char signature[13];
+
+ for (base = 0x40000000; base< 0x40010000; base += 0x100) {
+ cpuid(base,&eax,&ebx,&ecx,&edx);
+ *(uint32_t*)(signature + 0) = ebx;
+ *(uint32_t*)(signature + 4) = ecx;
+ *(uint32_t*)(signature + 8) = edx;
+ signature[12] = 0;
+
+ if (!strcmp("XenVMMXenVMM", signature)&& ((eax - base)>= 2))
+ return base;
+ }
+
+ return 0;
+}
+
+static int init_hvm_pv_info(void)
+{
+ uint32_t eax, ebx, ecx, edx, pages, msr, base;
+ u64 pfn;
+
+ base = xen_cpuid_base();
+ if (!base)
+ return -EINVAL;
+
+ cpuid(base + 1,&eax,&ebx,&ecx,&edx);
+
+ printk(KERN_INFO "Xen version %d.%d.\n", eax>> 16, eax& 0xffff);
+
+ cpuid(base + 2,&pages,&msr,&ecx,&edx);
+
+ /* We only support 1 page of hypercall for now */
+ if (pages != 1)
+ return -ENOMEM;

There's no point testing this; if we don't use hypercalls beyond the first page, it doesn't matter one way or the other.

+
+ pfn = __pa(hypercall_page);
+ wrmsrl(msr, pfn);

Use wrmsr_safe, just in case.

+
+ xen_setup_features();
+
+ pv_info = xen_info;
+ pv_info.kernel_rpl = 0;
+
+ xen_domain_type = XEN_HVM_DOMAIN;
+
+ return 0;
+}
+
+static void __init init_shared_info(void)
+{
+ struct xen_add_to_physmap xatp;
+ struct shared_info *shared_info_page;
+
+ shared_info_page = (struct shared_info *) alloc_bootmem_pages(PAGE_SIZE);
+ xatp.domid = DOMID_SELF;
+ xatp.idx = 0;
+ xatp.space = XENMAPSPACE_shared_info;
+ xatp.gpfn = __pa(shared_info_page)>> PAGE_SHIFT;
+ if (HYPERVISOR_memory_op(XENMEM_add_to_physmap,&xatp))
+ BUG();
+
+ HYPERVISOR_shared_info = (struct shared_info *)shared_info_page;
+
+ /* Don't do the full vcpu_info placement stuff until we have a
+ possible map and a non-dummy shared_info. */
+ per_cpu(xen_vcpu, 0) =&HYPERVISOR_shared_info->vcpu_info[0];
+}
+
+void __init xen_guest_init(void)
+{
+ int r;
+
+ r = init_hvm_pv_info();
+ if (r< 0)
+ return;
+
+ init_shared_info();
+}
+
diff --git a/drivers/input/xen-kbdfront.c b/drivers/input/xen-kbdfront.c
index b115726..bfbb13b 100644
--- a/drivers/input/xen-kbdfront.c
+++ b/drivers/input/xen-kbdfront.c
@@ -342,6 +342,9 @@ static int __init xenkbd_init(void)
if (xen_initial_domain())
return -ENODEV;

+ if (xen_hvm_domain())
+ return -ENODEV;

I think you can combine these into the same if(). Also put it in a separate patch.

+
return xenbus_register_frontend(&xenkbd_driver);
}

diff --git a/drivers/video/xen-fbfront.c b/drivers/video/xen-fbfront.c
index 54cd916..9d74c14 100644
--- a/drivers/video/xen-fbfront.c
+++ b/drivers/video/xen-fbfront.c
@@ -687,6 +687,9 @@ static int __init xenfb_init(void)
if (xen_initial_domain())
return -ENODEV;

+ if (xen_hvm_domain())
+ return -ENODEV;

Ditto.

+
return xenbus_register_frontend(&xenfb_driver);
}

diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index d42e25d..586b8f8 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -53,6 +53,8 @@
#include<xen/events.h>
#include<xen/page.h>

+#include<xen/hvm.h>
+
#include "xenbus_comms.h"
#include "xenbus_probe.h"

@@ -803,10 +805,19 @@ static int __init xenbus_probe_init(void)
/* dom0 not yet supported */
} else {
xenstored_ready = 1;
- xen_store_evtchn = xen_start_info->store_evtchn;
- xen_store_mfn = xen_start_info->store_mfn;
+ if (xen_hvm_domain()) {
+ xen_store_evtchn =
+ hvm_get_parameter(HVM_PARAM_STORE_EVTCHN);
+ xen_store_mfn =
+ hvm_get_parameter(HVM_PARAM_STORE_PFN);
+ xen_store_interface =
+ ioremap(xen_store_mfn<< PAGE_SHIFT, PAGE_SIZE);
+ } else {
+ xen_store_evtchn = xen_start_info->store_evtchn;
+ xen_store_mfn = xen_start_info->store_mfn;
+ xen_store_interface = mfn_to_virt(xen_store_mfn);
+ }
}
- xen_store_interface = mfn_to_virt(xen_store_mfn);

/* Initialize the interface to xenstore. */
err = xs_init();

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