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List: xen-devel
Subject: [Xen-devel] [PATCH v6 11/11] x86/hyperv: setup VP assist page
From: Wei Liu <wl () xen ! org>
Date: 2020-01-31 17:49:30
Message-ID: 20200131174930.31045-12-liuwe () microsoft ! com
[Download RAW message or body]
VP assist page is rather important as we need to toggle some bits in it
for efficient nested virtualisation.
Signed-off-by: Wei Liu <liuwe@microsoft.com>
---
v6:
1. Use hv_vp_assist_page_msr
2. Make code shorter
3. Preserve rsvdP fields
v5:
1. Deal with error properly instead of always panicking
2. Swap percpu variables declarations' location
v4:
1. Use private.h
2. Prevent leak
v3:
1. Use xenheap page
2. Drop set_vp_assist
v2:
1. Use HV_HYP_PAGE_SHIFT instead
---
xen/arch/x86/guest/hyperv/hyperv.c | 37 ++++++++++++++++++++++++++++-
xen/arch/x86/guest/hyperv/private.h | 1 +
2 files changed, 37 insertions(+), 1 deletion(-)
diff --git a/xen/arch/x86/guest/hyperv/hyperv.c b/xen/arch/x86/guest/hyperv/hyperv.c
index 6dac3bfceb..75fb329d4d 100644
--- a/xen/arch/x86/guest/hyperv/hyperv.c
+++ b/xen/arch/x86/guest/hyperv/hyperv.c
@@ -31,6 +31,7 @@
struct ms_hyperv_info __read_mostly ms_hyperv;
DEFINE_PER_CPU_READ_MOSTLY(void *, hv_input_page);
+DEFINE_PER_CPU_READ_MOSTLY(void *, hv_vp_assist);
DEFINE_PER_CPU_READ_MOSTLY(unsigned int, hv_vp_index);
static uint64_t generate_guest_id(void)
@@ -155,17 +156,51 @@ static int setup_hypercall_pcpu_arg(void)
return 0;
}
+static int setup_vp_assist(void)
+{
+ union hv_vp_assist_page_msr msr;
+
+ if ( !this_cpu(hv_vp_assist) )
+ {
+ this_cpu(hv_vp_assist) = alloc_xenheap_page();
+ if ( !this_cpu(hv_vp_assist) )
+ {
+ printk("CPU%u: Failed to allocate vp_assist page\n",
+ smp_processor_id());
+ return -ENOMEM;
+ }
+
+ clear_page(this_cpu(hv_vp_assist));
+ }
+
+ rdmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.raw);
+ msr.pfn = virt_to_mfn(this_cpu(hv_vp_assist));
+ msr.enabled = 1;
+ wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.raw);
+
+ return 0;
+}
+
static void __init setup(void)
{
setup_hypercall_page();
if ( setup_hypercall_pcpu_arg() )
panic("Hyper-V hypercall percpu arg setup failed\n");
+
+ if ( setup_vp_assist() )
+ panic("VP assist page setup failed\n");
}
static int ap_setup(void)
{
- return setup_hypercall_pcpu_arg();
+ int rc;
+
+ rc = setup_hypercall_pcpu_arg();
+ if ( rc )
+ return rc;
+
+ return setup_vp_assist();
}
static void __init e820_fixup(struct e820map *e820)
diff --git a/xen/arch/x86/guest/hyperv/private.h b/xen/arch/x86/guest/hyperv/private.h
index d1765d4f23..956eff831f 100644
--- a/xen/arch/x86/guest/hyperv/private.h
+++ b/xen/arch/x86/guest/hyperv/private.h
@@ -25,6 +25,7 @@
#include <xen/percpu.h>
DECLARE_PER_CPU(void *, hv_input_page);
+DECLARE_PER_CPU(void *, hv_vp_assist);
DECLARE_PER_CPU(unsigned int, hv_vp_index);
#endif /* __XEN_HYPERV_PRIVIATE_H__ */
--
2.20.1
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