Hi Andrew,
On 16/10/17 15:38, Andrew Cooper wrote:
* x86 PV and ARM dom0's must not clear _VPF_down from v->pause_flags until
all state is actually set up. As it currently stands, d0v0 is eligible for
scheduling before its registers have been set. This is latent as we also
hold a systemcontroller pause reference at the time which prevents d0 from
being scheduled.
* x86 PVH dom0's must set v->is_initialised on d0v0, to prevent another vcpu
being able to call VCPUOP_initialise and modify state under the feet of the
running vcpu. This is latent as PVH dom0 construction don't yet function.
Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
Release-acked-by: Julien Grall <julien.gr...@linaro.org>
Cheers,
---
CC: Jan Beulich <jbeul...@suse.com>
CC: Stefano Stabellini <sstabell...@kernel.org>
CC: Julien Grall <julien.gr...@arm.com>
CC: Wei Liu <wei.l...@citrix.com>
CC: Roger Pau Monné <roger....@citrix.com>
---
xen/arch/arm/domain_build.c | 6 +++---
xen/arch/x86/dom0_build.c | 13 +++++++++++--
xen/arch/x86/hvm/dom0_build.c | 1 +
xen/arch/x86/pv/dom0_build.c | 6 +++---
4 files changed, 18 insertions(+), 8 deletions(-)
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 4636b17..bf29299 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -2197,9 +2197,6 @@ int construct_dom0(struct domain *d)
discard_initial_modules();
- v->is_initialised = 1;
- clear_bit(_VPF_down, &v->pause_flags);
-
memset(regs, 0, sizeof(*regs));
regs->pc = (register_t)kinfo.entry;
@@ -2247,6 +2244,9 @@ int construct_dom0(struct domain *d)
vcpu_switch_to_aarch64_mode(d->vcpu[i]);
}
+ v->is_initialised = 1;
+ clear_bit(_VPF_down, &v->pause_flags);
+
return 0;
}
diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
index e4bffd5..bf992fe 100644
--- a/xen/arch/x86/dom0_build.c
+++ b/xen/arch/x86/dom0_build.c
@@ -466,6 +466,8 @@ int __init construct_dom0(struct domain *d, const module_t
*image,
void *(*bootstrap_map)(const module_t *),
char *cmdline)
{
+ int rc;
+
/* Sanity! */
BUG_ON(d->domain_id != 0);
BUG_ON(d->vcpu[0] == NULL);
@@ -481,8 +483,15 @@ int __init construct_dom0(struct domain *d, const module_t
*image,
}
#endif
- return (is_hvm_domain(d) ? dom0_construct_pvh : dom0_construct_pv)
- (d, image, image_headroom, initrd,bootstrap_map, cmdline);
+ rc = (is_hvm_domain(d) ? dom0_construct_pvh : dom0_construct_pv)
+ (d, image, image_headroom, initrd, bootstrap_map, cmdline);
+ if ( rc )
+ return rc;
+
+ /* Sanity! */
+ BUG_ON(!d->vcpu[0]->is_initialised);
+
+ return 0;
}
/*
diff --git a/xen/arch/x86/hvm/dom0_build.c b/xen/arch/x86/hvm/dom0_build.c
index e8f746c..a67071c 100644
--- a/xen/arch/x86/hvm/dom0_build.c
+++ b/xen/arch/x86/hvm/dom0_build.c
@@ -614,6 +614,7 @@ static int __init pvh_setup_cpus(struct domain *d, paddr_t
entry,
update_domain_wallclock_time(d);
+ v->is_initialised = 1;
clear_bit(_VPF_down, &v->pause_flags);
return 0;
diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c
index dcbee43..8ad7e3d 100644
--- a/xen/arch/x86/pv/dom0_build.c
+++ b/xen/arch/x86/pv/dom0_build.c
@@ -847,9 +847,6 @@ int __init dom0_construct_pv(struct domain *d,
update_domain_wallclock_time(d);
- v->is_initialised = 1;
- clear_bit(_VPF_down, &v->pause_flags);
-
/*
* Initial register values:
* DS,ES,FS,GS = FLAT_KERNEL_DS
@@ -883,6 +880,9 @@ int __init dom0_construct_pv(struct domain *d,
if ( d->domain_id == hardware_domid )
iommu_hwdom_init(d);
+ v->is_initialised = 1;
+ clear_bit(_VPF_down, &v->pause_flags);
+
return 0;
out:
--
Julien Grall
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