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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] x86: don't drop guest visible state updates when 64-bit PV guest is in user mode
commit 231d7f4098c8ac9cdb78f18fcb820d8618c8b0c2
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Jan 23 10:30:08 2014 +0100
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Jan 23 10:30:08 2014 +0100
x86: don't drop guest visible state updates when 64-bit PV guest is in user
mode
Since 64-bit PV uses separate kernel and user mode page tables, kernel
addresses (as usually provided via VCPUOP_register_runstate_memory_area
and possibly via VCPUOP_register_vcpu_time_memory_area) aren't
necessarily accessible when the respective updating occurs. Add logic
for toggle_guest_mode() to take care of this (if necessary) the next
time the vCPU switches to kernel mode.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
xen/arch/x86/domain.c | 24 ++++++++++++++++--------
xen/arch/x86/time.c | 39 +++++++++++++++++++++++++--------------
xen/arch/x86/x86_64/traps.c | 12 ++++++++++++
xen/include/asm-x86/domain.h | 8 ++++++++
4 files changed, 61 insertions(+), 22 deletions(-)
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index ae2d246..16f2b50 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -1323,10 +1323,10 @@ static void paravirt_ctxt_switch_to(struct vcpu *v)
}
/* Update per-VCPU guest runstate shared memory area (if registered). */
-static void update_runstate_area(struct vcpu *v)
+bool_t update_runstate_area(const struct vcpu *v)
{
if ( guest_handle_is_null(runstate_guest(v)) )
- return;
+ return 1;
if ( has_32bit_shinfo(v->domain) )
{
@@ -1334,10 +1334,18 @@ static void update_runstate_area(struct vcpu *v)
XLAT_vcpu_runstate_info(&info, &v->runstate);
__copy_to_guest(v->runstate_guest.compat, &info, 1);
- return;
+ return 1;
}
- __copy_to_guest(runstate_guest(v), &v->runstate, 1);
+ return __copy_to_guest(runstate_guest(v), &v->runstate, 1) !=
+ sizeof(v->runstate);
+}
+
+static void _update_runstate_area(struct vcpu *v)
+{
+ if ( !update_runstate_area(v) && is_pv_vcpu(v) &&
+ !(v->arch.flags & TF_kernel_mode) )
+ v->arch.pv_vcpu.need_update_runstate_area = 1;
}
static inline int need_full_gdt(struct vcpu *v)
@@ -1443,8 +1451,8 @@ void context_switch(struct vcpu *prev, struct vcpu *next)
flush_tlb_mask(&dirty_mask);
}
- if (prev != next)
- update_runstate_area(prev);
+ if ( prev != next )
+ _update_runstate_area(prev);
if ( is_hvm_vcpu(prev) )
{
@@ -1497,8 +1505,8 @@ void context_switch(struct vcpu *prev, struct vcpu *next)
context_saved(prev);
- if (prev != next)
- update_runstate_area(next);
+ if ( prev != next )
+ _update_runstate_area(next);
/* Ensure that the vcpu has an up-to-date time base. */
update_vcpu_system_time(next);
diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index e463600..6e31e1f 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -740,7 +740,6 @@ static void __update_vcpu_system_time(struct vcpu *v, int
force)
{
struct cpu_time *t;
struct vcpu_time_info *u, _u;
- XEN_GUEST_HANDLE(vcpu_time_info_t) user_u;
struct domain *d = v->domain;
s_time_t tsc_stamp = 0;
@@ -805,19 +804,31 @@ static void __update_vcpu_system_time(struct vcpu *v, int
force)
/* 3. Update guest kernel version. */
u->version = version_update_end(u->version);
- user_u = v->arch.time_info_guest;
- if ( !guest_handle_is_null(user_u) )
- {
- /* 1. Update userspace version. */
- __copy_field_to_guest(user_u, &_u, version);
- wmb();
- /* 2. Update all other userspavce fields. */
- __copy_to_guest(user_u, &_u, 1);
- wmb();
- /* 3. Update userspace version. */
- _u.version = version_update_end(_u.version);
- __copy_field_to_guest(user_u, &_u, version);
- }
+ if ( !update_secondary_system_time(v, &_u) && is_pv_domain(d) &&
+ !is_pv_32bit_domain(d) && !(v->arch.flags & TF_kernel_mode) )
+ v->arch.pv_vcpu.pending_system_time = _u;
+}
+
+bool_t update_secondary_system_time(const struct vcpu *v,
+ struct vcpu_time_info *u)
+{
+ XEN_GUEST_HANDLE(vcpu_time_info_t) user_u = v->arch.time_info_guest;
+
+ if ( guest_handle_is_null(user_u) )
+ return 1;
+
+ /* 1. Update userspace version. */
+ if ( __copy_field_to_guest(user_u, u, version) == sizeof(u->version) )
+ return 0;
+ wmb();
+ /* 2. Update all other userspace fields. */
+ __copy_to_guest(user_u, u, 1);
+ wmb();
+ /* 3. Update userspace version. */
+ u->version = version_update_end(u->version);
+ __copy_field_to_guest(user_u, u, version);
+
+ return 1;
}
void update_vcpu_system_time(struct vcpu *v)
diff --git a/xen/arch/x86/x86_64/traps.c b/xen/arch/x86/x86_64/traps.c
index ad09415..d8303f9 100644
--- a/xen/arch/x86/x86_64/traps.c
+++ b/xen/arch/x86/x86_64/traps.c
@@ -266,6 +266,18 @@ void toggle_guest_mode(struct vcpu *v)
#else
write_ptbase(v);
#endif
+
+ if ( !(v->arch.flags & TF_kernel_mode) )
+ return;
+
+ if ( v->arch.pv_vcpu.need_update_runstate_area &&
+ update_runstate_area(v) )
+ v->arch.pv_vcpu.need_update_runstate_area = 0;
+
+ if ( v->arch.pv_vcpu.pending_system_time.version &&
+ update_secondary_system_time(v,
+ &v->arch.pv_vcpu.pending_system_time) )
+ v->arch.pv_vcpu.pending_system_time.version = 0;
}
unsigned long do_iret(void)
diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
index 9d39061..ea72db2 100644
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -373,6 +373,10 @@ struct pv_vcpu
/* Current LDT details. */
unsigned long shadow_ldt_mapcnt;
spinlock_t shadow_ldt_lock;
+
+ /* Deferred VA-based update state. */
+ bool_t need_update_runstate_area;
+ struct vcpu_time_info pending_system_time;
};
struct arch_vcpu
@@ -445,6 +449,10 @@ struct arch_vcpu
#define hvm_vmx hvm_vcpu.u.vmx
#define hvm_svm hvm_vcpu.u.svm
+bool_t update_runstate_area(const struct vcpu *);
+bool_t update_secondary_system_time(const struct vcpu *,
+ struct vcpu_time_info *);
+
void vcpu_show_execution_state(struct vcpu *);
void vcpu_show_registers(const struct vcpu *);
--
generated by git-patchbot for /home/xen/git/xen.git#master
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