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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] x86/HVM: fix preemption handling in do_hvm_op()
commit 8bad6c5626129ffba04dbab3a38115b6f3669596
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri Mar 28 13:31:23 2014 +0100
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Mar 28 13:31:23 2014 +0100
x86/HVM: fix preemption handling in do_hvm_op()
Just like previously done for some mem-op hypercalls, undo preemption
using the interface structures (altering it in ways the caller may not
expect) and replace it by storing the continuation point in the high
bits of sub-operation argument.
This also changes the "nr" fields of struct xen_hvm_track_dirty_vram
(operation already limited to 1Gb worth of pages) and struct
xen_hvm_modified_memory to be only 32 bits wide, consistent with those
of struct xen_set_mem{type,access}. If that's not acceptable for some
reason, we'd need to shrink the HVMOP_op_bits (while still enforcing
the [then higher] limit resulting from the need to be able to encode
the continuation).
Whether (and if so how) to adjust xc_hvm_track_dirty_vram(),
xc_hvm_modified_memory(), xc_hvm_set_mem_type(), and
xc_hvm_set_mem_access() to reflect the 32-bit restriction on "nr" is
unclear: If the APIs need to remain stable, all four functions should
probably check that there was no truncation. Preferably their
parameters would be changed to uint32_t or unsigned int, though.
As a minor cleanup, along with introducing the switch-wide "pfn" the
redundant "d" is also being converted to a switch-wide one.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Tim Deegan <tim@xxxxxxx>
---
xen/arch/x86/hvm/hvm.c | 77 +++++++++++++++++----------------------
xen/include/public/hvm/hvm_op.h | 8 ++--
2 files changed, 37 insertions(+), 48 deletions(-)
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index c74287d..d844c8c 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4053,20 +4053,25 @@ static int hvm_replace_event_channel(struct vcpu *v,
domid_t remote_domid,
return 0;
}
+#define HVMOP_op_bits 32
+
long do_hvm_op(unsigned long op, XEN_GUEST_HANDLE_PARAM(void) arg)
{
struct domain *curr_d = current->domain;
+ unsigned long start_iter = op >> HVMOP_op_bits;
long rc = 0;
- switch ( op )
+ switch ( op &= ((1UL << HVMOP_op_bits) - 1) )
{
+ struct domain *d;
+ unsigned long pfn;
+
case HVMOP_set_param:
case HVMOP_get_param:
{
struct xen_hvm_param a;
struct hvm_ioreq_page *iorp;
- struct domain *d;
struct vcpu *v;
if ( copy_from_guest(&a, arg, 1) )
@@ -4330,7 +4335,6 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
case HVMOP_track_dirty_vram:
{
struct xen_hvm_track_dirty_vram a;
- struct domain *d;
if ( copy_from_guest(&a, arg, 1) )
return -EFAULT;
@@ -4371,7 +4375,6 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
case HVMOP_modified_memory:
{
struct xen_hvm_modified_memory a;
- struct domain *d;
if ( copy_from_guest(&a, arg, 1) )
return -EFAULT;
@@ -4389,7 +4392,8 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
goto param_fail3;
rc = -EINVAL;
- if ( ((a.first_pfn + a.nr - 1) < a.first_pfn) ||
+ if ( a.nr < start_iter ||
+ ((a.first_pfn + a.nr - 1) < a.first_pfn) ||
((a.first_pfn + a.nr - 1) > domain_get_maximum_gpfn(d)) )
goto param_fail3;
@@ -4397,9 +4401,8 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
if ( !paging_mode_log_dirty(d) )
goto param_fail3;
- while ( a.nr > 0 )
+ for ( pfn = a.first_pfn + start_iter; a.nr > start_iter; ++pfn )
{
- unsigned long pfn = a.first_pfn;
struct page_info *page;
page = get_page_from_gfn(d, pfn, NULL, P2M_UNSHARE);
@@ -4412,16 +4415,13 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
put_page(page);
}
- a.first_pfn++;
- a.nr--;
+ ++pfn;
+ ++start_iter;
/* Check for continuation if it's not the last interation */
- if ( a.nr > 0 && hypercall_preempt_check() )
+ if ( a.nr > start_iter && hypercall_preempt_check() )
{
- if ( __copy_to_guest(arg, &a, 1) )
- rc = -EFAULT;
- else
- rc = -EAGAIN;
+ rc = -EAGAIN;
break;
}
}
@@ -4434,7 +4434,6 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
case HVMOP_get_mem_type:
{
struct xen_hvm_get_mem_type a;
- struct domain *d;
p2m_type_t t;
if ( copy_from_guest(&a, arg, 1) )
@@ -4478,7 +4477,6 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
case HVMOP_set_mem_type:
{
struct xen_hvm_set_mem_type a;
- struct domain *d;
/* Interface types to internal p2m types */
static const p2m_type_t memtype[] = {
@@ -4503,20 +4501,19 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
goto param_fail4;
rc = -EINVAL;
- if ( ((a.first_pfn + a.nr - 1) < a.first_pfn) ||
+ if ( a.nr < start_iter ||
+ ((a.first_pfn + a.nr - 1) < a.first_pfn) ||
((a.first_pfn + a.nr - 1) > domain_get_maximum_gpfn(d)) )
goto param_fail4;
if ( a.hvmmem_type >= ARRAY_SIZE(memtype) )
goto param_fail4;
- while ( a.nr )
+ for ( pfn = a.first_pfn + start_iter; a.nr > start_iter; ++pfn )
{
- unsigned long pfn = a.first_pfn;
- p2m_type_t t;
- p2m_type_t nt;
- mfn_t mfn;
- mfn = get_gfn_unshare(d, pfn, &t);
+ p2m_type_t t, nt;
+
+ get_gfn_unshare(d, pfn, &t);
if ( p2m_is_paging(t) )
{
put_gfn(d, pfn);
@@ -4553,16 +4550,13 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
}
put_gfn(d, pfn);
- a.first_pfn++;
- a.nr--;
+ ++pfn;
+ ++start_iter;
/* Check for continuation if it's not the last interation */
- if ( a.nr > 0 && hypercall_preempt_check() )
+ if ( a.nr > start_iter && hypercall_preempt_check() )
{
- if ( __copy_to_guest(arg, &a, 1) )
- rc = -EFAULT;
- else
- rc = -EAGAIN;
+ rc = -EAGAIN;
goto param_fail4;
}
}
@@ -4577,7 +4571,6 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
case HVMOP_set_mem_access:
{
struct xen_hvm_set_mem_access a;
- struct domain *d;
if ( copy_from_guest(&a, arg, 1) )
return -EFAULT;
@@ -4596,19 +4589,17 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
rc = -EINVAL;
if ( (a.first_pfn != ~0ull) &&
- (((a.first_pfn + a.nr - 1) < a.first_pfn) ||
+ (a.nr < start_iter ||
+ ((a.first_pfn + a.nr - 1) < a.first_pfn) ||
((a.first_pfn + a.nr - 1) > domain_get_maximum_gpfn(d))) )
goto param_fail5;
- rc = p2m_set_mem_access(d, a.first_pfn, a.nr, a.hvmmem_access);
+ rc = p2m_set_mem_access(d, a.first_pfn + start_iter, a.nr - start_iter,
+ a.hvmmem_access);
if ( rc > 0 )
{
- a.first_pfn += a.nr - rc;
- a.nr = rc;
- if ( __copy_to_guest(arg, &a, 1) )
- rc = -EFAULT;
- else
- rc = -EAGAIN;
+ start_iter = a.nr - rc;
+ rc = -EAGAIN;
}
param_fail5:
@@ -4619,7 +4610,6 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
case HVMOP_get_mem_access:
{
struct xen_hvm_get_mem_access a;
- struct domain *d;
hvmmem_access_t access;
if ( copy_from_guest(&a, arg, 1) )
@@ -4656,7 +4646,6 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
case HVMOP_pagetable_dying:
{
struct xen_hvm_pagetable_dying a;
- struct domain *d;
if ( copy_from_guest(&a, arg, 1) )
return -EFAULT;
@@ -4709,7 +4698,6 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
case HVMOP_inject_trap:
{
xen_hvm_inject_trap_t tr;
- struct domain *d;
struct vcpu *v;
if ( copy_from_guest(&tr, arg, 1 ) )
@@ -4757,8 +4745,9 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
}
if ( rc == -EAGAIN )
- rc = hypercall_create_continuation(
- __HYPERVISOR_hvm_op, "lh", op, arg);
+ rc = hypercall_create_continuation(__HYPERVISOR_hvm_op, "lh",
+ op | (start_iter << HVMOP_op_bits),
+ arg);
return rc;
}
diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
index a9aab4b..3204ec4 100644
--- a/xen/include/public/hvm/hvm_op.h
+++ b/xen/include/public/hvm/hvm_op.h
@@ -90,10 +90,10 @@ typedef enum {
struct xen_hvm_track_dirty_vram {
/* Domain to be tracked. */
domid_t domid;
+ /* Number of pages to track. */
+ uint32_t nr;
/* First pfn to track. */
uint64_aligned_t first_pfn;
- /* Number of pages to track. */
- uint64_aligned_t nr;
/* OUT variable. */
/* Dirty bitmap buffer. */
XEN_GUEST_HANDLE_64(uint8) dirty_bitmap;
@@ -106,10 +106,10 @@ DEFINE_XEN_GUEST_HANDLE(xen_hvm_track_dirty_vram_t);
struct xen_hvm_modified_memory {
/* Domain to be updated. */
domid_t domid;
+ /* Number of pages. */
+ uint32_t nr;
/* First pfn. */
uint64_aligned_t first_pfn;
- /* Number of pages. */
- uint64_aligned_t nr;
};
typedef struct xen_hvm_modified_memory xen_hvm_modified_memory_t;
DEFINE_XEN_GUEST_HANDLE(xen_hvm_modified_memory_t);
--
generated by git-patchbot for /home/xen/git/xen.git#master
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