/*
* Xen stolen ticks accounting.
*/
#include <linux/kernel.h>
#include <linux/kernel_stat.h>
#include <linux/math64.h>
#include <linux/gfp.h>
#include <asm/paravirt.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
#include <xen/events.h>
#include <xen/features.h>
#include <xen/interface/xen.h>
#include <xen/interface/vcpu.h>
#include <xen/xen-ops.h>
/* runstate info updated by Xen */
static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate);
/* return an consistent snapshot of 64-bit time/counter value */
static u64 get64(const u64 *p)
{
u64 ret;
if (BITS_PER_LONG < 64) {
u32 *p32 = (u32 *)p;
u32 h, l, h2;
/*
* Read high then low, and then make sure high is
* still the same; this will only loop if low wraps
* and carries into high.
* XXX some clean way to make this endian-proof?
*/
do {
h = READ_ONCE(p32[1]);
l = READ_ONCE(p32[0]);
h2 = READ_ONCE(p32[1]);
} while(h2 != h);
ret = (((u64)h) << 32) | l;
} else
ret = READ_ONCE(*p);
return ret;
}
static void xen_get_runstate_snapshot_cpu(struct vcpu_runstate_info *res,
unsigned int cpu)
{
u64 state_time;
struct vcpu_runstate_info *state;
BUG_ON(preemptible());
state = per_cpu_ptr(&xen_runstate, cpu);
do {
state_time = get64(&state->state_entry_time);
rmb(); /* Hypervisor might update data. */
*res = READ_ONCE(*state);
rmb(); /* Hypervisor might update data. */
} while (get64(&state->state_entry_time) != state_time ||
(state_time & XEN_RUNSTATE_UPDATE));
}
/*
* Runstate accounting
*/
void xen_get_runstate_snapshot(struct vcpu_runstate_info *res)
{
xen_get_runstate_snapshot_cpu(res, smp_processor_id());
}
/* return true when a vcpu could run but has no real cpu to run on */
bool xen_vcpu_stolen(int vcpu)
{
return per_cpu(xen_runstate, vcpu).state == RUNSTATE_runnable;
}
u64 xen_steal_clock(int cpu)
{
struct vcpu_runstate_info state;
xen_get_runstate_snapshot_cpu(&state, cpu);
return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline];
}
void xen_setup_runstate_info(int cpu)
{
struct vcpu_register_runstate_memory_area area;
area.addr.v = &per_cpu(xen_runstate, cpu);
if (HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area,
xen_vcpu_nr(cpu), &area))
BUG();
}
void __init xen_time_setup_guest(void)
{
bool xen_runstate_remote;
xen_runstate_remote = !HYPERVISOR_vm_assist(VMASST_CMD_enable,
VMASST_TYPE_runstate_update_flag);
pv_time_ops.steal_clock = xen_steal_clock;
static_key_slow_inc(¶virt_steal_enabled);
if (xen_runstate_remote)
static_key_slow_inc(¶virt_steal_rq_enabled);
}
href='/cgit.cgi/linux/net-next.git/commit/?id=433e19cf33d34bb6751c874a9c00980552fe508c'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include?id=433e19cf33d34bb6751c874a9c00980552fe508c'>include</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include/kvm?id=433e19cf33d34bb6751c874a9c00980552fe508c'>kvm</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='433e19cf33d34bb6751c874a9c00980552fe508c'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Dexuan Cui <decui@microsoft.com></td><td class='right'>2017-01-28 11:46:02 -0700</td></tr>
<tr><th>committer</th><td>Greg Kroah-Hartman <gregkh@linuxfoundation.org></td><td class='right'>2017-01-31 10:59:48 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/kvm?id=433e19cf33d34bb6751c874a9c00980552fe508c'>433e19cf33d34bb6751c874a9c00980552fe508c</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/kvm?id=433e19cf33d34bb6751c874a9c00980552fe508c'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=433e19cf33d34bb6751c874a9c00980552fe508c'>ce6547ef2987fbb289fa28f03536328a42781651</a> /<a href='/cgit.cgi/linux/net-next.git/tree/include/kvm?id=433e19cf33d34bb6751c874a9c00980552fe508c'>include/kvm</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/kvm?id=191e885a2e130e639bb0c8ee350d7047294f2ce6'>191e885a2e130e639bb0c8ee350d7047294f2ce6</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/kvm?id=433e19cf33d34bb6751c874a9c00980552fe508c&id2=191e885a2e130e639bb0c8ee350d7047294f2ce6'>diff</a>)</td></tr></table>
<div class='commit-subject'>Drivers: hv: vmbus: finally fix hv_need_to_signal_on_read()</div><div class='commit-msg'>Commit a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")
added the proper mb(), but removed the test "prev_write_sz < pending_sz"
when making the signal decision.
As a result, the guest can signal the host unnecessarily,
and then the host can throttle the guest because the host
thinks the guest is buggy or malicious; finally the user
running stress test can perceive intermittent freeze of
the guest.
This patch brings back the test, and properly handles the
in-place consumption APIs used by NetVSC (see get_next_pkt_raw(),
put_pkt_raw() and commit_rd_index()).
Fixes: a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reported-by: Rolf Neugebauer <rolf.neugebauer@docker.com>
Tested-by: Rolf Neugebauer <rolf.neugebauer@docker.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=433e19cf33d34bb6751c874a9c00980552fe508c'>Diffstat</a> (limited to 'include/kvm')</div><table summary='diffstat' class='diffstat'>