From: Paul Durrant <paul.durrant@citrix.com>
To: xen-devel@lists.xenproject.org
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
Paul Durrant <paul.durrant@citrix.com>,
Keir Fraser <keir@xen.org>, Jan Beulich <jbeulich@suse.com>
Subject: [PATCH v4 1/2] x86/hvm/viridian: keep APIC assist page mapped...
Date: Thu, 17 Mar 2016 08:37:32 +0000 [thread overview]
Message-ID: <1458203853-4441-2-git-send-email-paul.durrant@citrix.com> (raw)
In-Reply-To: <1458203853-4441-1-git-send-email-paul.durrant@citrix.com>
... for the lifetime of the domain.
If Xen is to make use of the APIC assist enlightenment then a persistent
mapping needs to be kept, rather than the temporary one which is currently
used only to initialize the page content.
This patch also adds a comment block at the top of the source with
information on the latest version of the spec. from Microsoft and the
current URL where it may be found.
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
---
v4:
- Added missing teardown required if the MSR is re-written.
v2:
- Re-instated warning if the initialization of an APIC assist page fails.
- Added up-to-date information about the viridian specification to the
comment block at the top of the source.
---
xen/arch/x86/hvm/hvm.c | 2 +
xen/arch/x86/hvm/viridian.c | 77 ++++++++++++++++++++++++++++----------
xen/include/asm-x86/hvm/viridian.h | 8 +++-
3 files changed, 66 insertions(+), 21 deletions(-)
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 4ea51d7..f446ee4 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -2606,6 +2606,8 @@ int hvm_vcpu_initialise(struct vcpu *v)
void hvm_vcpu_destroy(struct vcpu *v)
{
+ viridian_vcpu_deinit(v);
+
hvm_all_ioreq_servers_remove_vcpu(v->domain, v);
if ( hvm_altp2m_supported() )
diff --git a/xen/arch/x86/hvm/viridian.c b/xen/arch/x86/hvm/viridian.c
index 1ee22aa..b809118 100644
--- a/xen/arch/x86/hvm/viridian.c
+++ b/xen/arch/x86/hvm/viridian.c
@@ -1,7 +1,12 @@
/******************************************************************************
* viridian.c
*
- * An implementation of the Viridian hypercall interface.
+ * An implementation of some Viridian enlightenments. See Microsoft's
+ * Hypervisor Top Level Functional Specification (v4.0b) at:
+ *
+ * https://msdn.microsoft.com/en-us/virtualization/hyperv_on_windows/develop/tlfs
+ *
+ * for more information.
*/
#include <xen/sched.h>
@@ -163,7 +168,7 @@ static void dump_apic_assist(const struct vcpu *v)
{
const union viridian_apic_assist *aa;
- aa = &v->arch.hvm_vcpu.viridian.apic_assist;
+ aa = &v->arch.hvm_vcpu.viridian.apic_assist.msr;
printk(XENLOG_G_INFO "%pv: VIRIDIAN APIC_ASSIST: enabled: %x pfn: %lx\n",
v, aa->fields.enabled, (unsigned long)aa->fields.pfn);
@@ -217,9 +222,9 @@ static void enable_hypercall_page(struct domain *d)
static void initialize_apic_assist(struct vcpu *v)
{
struct domain *d = v->domain;
- unsigned long gmfn = v->arch.hvm_vcpu.viridian.apic_assist.fields.pfn;
+ unsigned long gmfn = v->arch.hvm_vcpu.viridian.apic_assist.msr.fields.pfn;
struct page_info *page = get_page_from_gfn(d, gmfn, NULL, P2M_ALLOC);
- uint8_t *p;
+ void *va;
/*
* We don't yet make use of the APIC assist page but by setting
@@ -227,25 +232,49 @@ static void initialize_apic_assist(struct vcpu *v)
* bound to support the MSR. We therefore do just enough to keep windows
* happy.
*
- * See http://msdn.microsoft.com/en-us/library/ff538657%28VS.85%29.aspx for
- * details of how Windows uses the page.
+ * See section 13.3.4.1 of the specification for details of this
+ * enlightenment.
*/
- if ( !page || !get_page_type(page, PGT_writable_page) )
+ if ( !page )
+ goto fail;
+
+ if ( !get_page_type(page, PGT_writable_page) )
{
- if ( page )
- put_page(page);
- gdprintk(XENLOG_WARNING, "Bad GMFN %lx (MFN %lx)\n", gmfn,
- page ? page_to_mfn(page) : INVALID_MFN);
- return;
+ put_page(page);
+ goto fail;
}
- p = __map_domain_page(page);
+ va = __map_domain_page_global(page);
+ if ( !va )
+ {
+ put_page_and_type(page);
+ goto fail;
+ }
- *(u32 *)p = 0;
+ *(uint32_t *)va = 0;
- unmap_domain_page(p);
+ v->arch.hvm_vcpu.viridian.apic_assist.page = page;
+ v->arch.hvm_vcpu.viridian.apic_assist.va = va;
+ return;
+
+ fail:
+ gdprintk(XENLOG_WARNING, "Bad GMFN %lx (MFN %lx)\n", gmfn,
+ page ? page_to_mfn(page) : INVALID_MFN);
+}
+
+static void teardown_apic_assist(struct vcpu *v)
+{
+ struct page_info *page = v->arch.hvm_vcpu.viridian.apic_assist.page;
+ void *va = v->arch.hvm_vcpu.viridian.apic_assist.va;
+ if ( !va )
+ return;
+
+ v->arch.hvm_vcpu.viridian.apic_assist.va = NULL;
+ v->arch.hvm_vcpu.viridian.apic_assist.page = NULL;
+
+ unmap_domain_page_global(va);
put_page_and_type(page);
}
@@ -374,9 +403,10 @@ int wrmsr_viridian_regs(uint32_t idx, uint64_t val)
case VIRIDIAN_MSR_APIC_ASSIST:
perfc_incr(mshv_wrmsr_apic_msr);
- v->arch.hvm_vcpu.viridian.apic_assist.raw = val;
+ teardown_apic_assist(v); /* release any previous mapping */
+ v->arch.hvm_vcpu.viridian.apic_assist.msr.raw = val;
dump_apic_assist(v);
- if (v->arch.hvm_vcpu.viridian.apic_assist.fields.enabled)
+ if ( v->arch.hvm_vcpu.viridian.apic_assist.msr.fields.enabled )
initialize_apic_assist(v);
break;
@@ -485,7 +515,7 @@ int rdmsr_viridian_regs(uint32_t idx, uint64_t *val)
case VIRIDIAN_MSR_APIC_ASSIST:
perfc_incr(mshv_rdmsr_apic_msr);
- *val = v->arch.hvm_vcpu.viridian.apic_assist.raw;
+ *val = v->arch.hvm_vcpu.viridian.apic_assist.msr.raw;
break;
case VIRIDIAN_MSR_REFERENCE_TSC:
@@ -521,6 +551,11 @@ int rdmsr_viridian_regs(uint32_t idx, uint64_t *val)
return 1;
}
+void viridian_vcpu_deinit(struct vcpu *v)
+{
+ teardown_apic_assist(v);
+}
+
static DEFINE_PER_CPU(cpumask_t, ipi_cpumask);
int viridian_hypercall(struct cpu_user_regs *regs)
@@ -721,7 +756,7 @@ static int viridian_save_vcpu_ctxt(struct domain *d, hvm_domain_context_t *h)
for_each_vcpu( d, v ) {
struct hvm_viridian_vcpu_context ctxt;
- ctxt.apic_assist = v->arch.hvm_vcpu.viridian.apic_assist.raw;
+ ctxt.apic_assist = v->arch.hvm_vcpu.viridian.apic_assist.msr.raw;
if ( hvm_save_entry(VIRIDIAN_VCPU, v->vcpu_id, h, &ctxt) != 0 )
return 1;
@@ -747,7 +782,9 @@ static int viridian_load_vcpu_ctxt(struct domain *d, hvm_domain_context_t *h)
if ( hvm_load_entry(VIRIDIAN_VCPU, h, &ctxt) != 0 )
return -EINVAL;
- v->arch.hvm_vcpu.viridian.apic_assist.raw = ctxt.apic_assist;
+ v->arch.hvm_vcpu.viridian.apic_assist.msr.raw = ctxt.apic_assist;
+ if ( v->arch.hvm_vcpu.viridian.apic_assist.msr.fields.enabled )
+ initialize_apic_assist(v);
return 0;
}
diff --git a/xen/include/asm-x86/hvm/viridian.h b/xen/include/asm-x86/hvm/viridian.h
index c4319d7..ee3a120 100644
--- a/xen/include/asm-x86/hvm/viridian.h
+++ b/xen/include/asm-x86/hvm/viridian.h
@@ -21,7 +21,11 @@ union viridian_apic_assist
struct viridian_vcpu
{
- union viridian_apic_assist apic_assist;
+ struct {
+ union viridian_apic_assist msr;
+ struct page_info *page;
+ void *va;
+ } apic_assist;
};
union viridian_guest_os_id
@@ -117,6 +121,8 @@ viridian_hypercall(struct cpu_user_regs *regs);
void viridian_time_ref_count_freeze(struct domain *d);
void viridian_time_ref_count_thaw(struct domain *d);
+void viridian_vcpu_deinit(struct vcpu *v);
+
#endif /* __ASM_X86_HVM_VIRIDIAN_H__ */
/*
--
2.1.4
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next prev parent reply other threads:[~2016-03-17 8:48 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-17 8:37 [PATCH v4 0/2] x86/hvm/viridian: APIC assist Paul Durrant
2016-03-17 8:37 ` Paul Durrant [this message]
2016-03-17 10:50 ` [PATCH v4 1/2] x86/hvm/viridian: keep APIC assist page mapped Andrew Cooper
2016-03-17 11:13 ` Paul Durrant
2016-03-17 11:58 ` Jan Beulich
2016-03-17 12:00 ` Paul Durrant
2016-03-17 8:37 ` [PATCH v4 2/2] x86/hvm/viridian: Enable APIC assist enlightenment Paul Durrant
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