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[xen master] xen/memory: Remove tail padding from TRC_MEM_* records
commit 83af664db3366d9c3047abd67655dce1796d005c
Author: Andrew Cooper <andrew.cooper3@citrix.com>
AuthorDate: Wed Sep 15 16:49:01 2021 +0100
Commit: Andrew Cooper <andrew.cooper3@citrix.com>
CommitDate: Fri Mar 24 15:35:37 2023 +0000

xen/memory: Remove tail padding from TRC_MEM_* records

Four TRC_MEM_* records supply custom structures with tail padding, leaking
stack rubble into the trace buffer. Three of the records were fine in 32-bit
builds of Xen, due to the relaxed alignment of 64-bit integers, but
POD_SUPERPAGE_SPLITER was broken right from the outset.

We could pack the datastructures to remove the padding, but xentrace_format
has no way of rendering the upper half of a 16-bit field. Instead, expand all
16-bit fields to 32-bit.

For POD_SUPERPAGE_SPLINTER, introduce an order field as it is relevant
information, and to match DECREASE_RESERVATION, and so it doesn't require a
__packed attribute to drop tail padding.

Update xenalyze's structures to match, and introduce xentrace_format rendering
which was absent previously.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Dario Faggioli <dfaggioli@suse.com>
---
tools/xentrace/formats | 4 ++++
tools/xentrace/xenalyze.c | 12 ++++++------
xen/arch/x86/mm/p2m-pod.c | 17 +++++++++--------
xen/common/memory.c | 4 ++--
4 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/tools/xentrace/formats b/tools/xentrace/formats
index deac4d8598..0fcc327a40 100644
--- a/tools/xentrace/formats
+++ b/tools/xentrace/formats
@@ -136,6 +136,10 @@
0x0010f001 CPU%(cpu)d %(tsc)d (+%(reltsc)8d) page_grant_map [ domid = %(1)d ]
0x0010f002 CPU%(cpu)d %(tsc)d (+%(reltsc)8d) page_grant_unmap [ domid = %(1)d ]
0x0010f003 CPU%(cpu)d %(tsc)d (+%(reltsc)8d) page_grant_transfer [ domid = %(1)d ]
+0x0010f005 CPU%(cpu)d %(tsc)d (+%(reltsc)8d) decrease_reservation [ d%(3)d gfn 0x%(2)08x%(1)08x, order %(4)u ]
+0x0010f010 CPU%(cpu)d %(tsc)d (+%(reltsc)8d) pod_populate [ d%(5)d gfn 0x%(2)08x%(1)08x => mfn 0x%(4)08x%(3)08x, order %(6)u ]
+0x0010f011 CPU%(cpu)d %(tsc)d (+%(reltsc)8d) pod_zero_reclaim [ d%(5)d gfn 0x%(2)08x%(1)08x => mfn 0x%(4)08x%(3)08x, order %(6)u ]
+0x0010f012 CPU%(cpu)d %(tsc)d (+%(reltsc)8d) pod_superpage_splinter [ d%(3)d gfn 0x%(2)08x%(1)08x, order %(4)u ]

0x00201001 CPU%(cpu)d %(tsc)d (+%(reltsc)8d) hypercall [ eip = 0x%(1)08x, eax = 0x%(2)08x ]
0x00201101 CPU%(cpu)d %(tsc)d (+%(reltsc)8d) hypercall [ rip = 0x%(2)08x%(1)08x, eax = 0x%(3)08x ]
diff --git a/tools/xentrace/xenalyze.c b/tools/xentrace/xenalyze.c
index 5de167031e..12dcca9646 100644
--- a/tools/xentrace/xenalyze.c
+++ b/tools/xentrace/xenalyze.c
@@ -8121,7 +8121,7 @@ void mem_pod_zero_reclaim_process(struct pcpu_info *p)

struct {
uint64_t gfn, mfn;
- int d:16,order:16;
+ uint32_t d, order;
} *r = (typeof(r))ri->d;

if ( v && v->hvm.vmexit_valid )
@@ -8171,7 +8171,7 @@ void mem_pod_populate_process(struct pcpu_info *p)

struct {
uint64_t gfn, mfn;
- int d:16,order:16;
+ uint32_t d, order;
} *r = (typeof(r))ri->d;

if ( opt.dump_all )
@@ -8204,14 +8204,14 @@ void mem_pod_superpage_splinter_process(struct pcpu_info *p)

struct {
uint64_t gfn;
- int d:16;
+ uint32_t d, order;
} *r = (typeof(r))ri->d;

if ( opt.dump_all )
{
- printf(" %s pod_spage_splinter d%d g %llx\n",
+ printf(" %s pod_spage_splinter d%d o%d g %"PRIx64"\n",
ri->dump_header,
- r->d, (unsigned long long)r->gfn);
+ r->d, r->order, r->gfn);
}
}

@@ -8255,7 +8255,7 @@ void mem_decrease_reservation_process(struct pcpu_info *p)

struct {
uint64_t gfn;
- int d:16,order:16;
+ uint32_t d, order;
} *r = (typeof(r))ri->d;

if ( opt.dump_all )
diff --git a/xen/arch/x86/mm/p2m-pod.c b/xen/arch/x86/mm/p2m-pod.c
index 2edab5e5cd..c75a60c19f 100644
--- a/xen/arch/x86/mm/p2m-pod.c
+++ b/xen/arch/x86/mm/p2m-pod.c
@@ -868,8 +868,8 @@ p2m_pod_zero_check_superpage(struct p2m_domain *p2m, gfn_t gfn)
if ( tb_init_done )
{
struct {
- u64 gfn, mfn;
- int d:16,order:16;
+ uint64_t gfn, mfn;
+ uint32_t d, order;
} t;

t.gfn = gfn_x(gfn);
@@ -1036,8 +1036,8 @@ p2m_pod_zero_check(struct p2m_domain *p2m, const gfn_t *gfns, unsigned int count
if ( tb_init_done )
{
struct {
- u64 gfn, mfn;
- int d:16,order:16;
+ uint64_t gfn, mfn;
+ uint32_t d, order;
} t;

t.gfn = gfn_x(gfns[i]);
@@ -1276,8 +1276,8 @@ p2m_pod_demand_populate(struct p2m_domain *p2m, gfn_t gfn,
if ( tb_init_done )
{
struct {
- u64 gfn, mfn;
- int d:16,order:16;
+ uint64_t gfn, mfn;
+ uint32_t d, order;
} t;

t.gfn = gfn_x(gfn);
@@ -1322,12 +1322,13 @@ remap_and_retry:
if ( tb_init_done )
{
struct {
- u64 gfn;
- int d:16;
+ uint64_t gfn;
+ uint32_t d, order;
} t;

t.gfn = gfn_x(gfn);
t.d = d->domain_id;
+ t.order = order;

__trace_var(TRC_MEM_POD_SUPERPAGE_SPLINTER, 0, sizeof(t), &t);
}
diff --git a/xen/common/memory.c b/xen/common/memory.c
index a15e5580f3..c206fa4808 100644
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -474,8 +474,8 @@ static void decrease_reservation(struct memop_args *a)
if ( tb_init_done )
{
struct {
- u64 gfn;
- int d:16,order:16;
+ uint64_t gfn;
+ uint32_t d, order;
} t;

t.gfn = gmfn;
--
generated by git-patchbot for /home/xen/git/xen.git#master