On 9/9/2016 1:24 PM, Yu Zhang wrote:
On 9/2/2016 6:47 PM, Yu Zhang wrote:
Routine hvmemul_do_io() may need to peek the p2m type of a gfn to
select the ioreq server. For example, operations on gfns with
p2m_ioreq_server type will be delivered to a corresponding ioreq
server, and this requires that the p2m type not be switched back
to p2m_ram_rw during the emulation process. To avoid this race
condition, we delay the release of p2m lock in
hvm_hap_nested_page_fault()
until mmio is handled.
Note: previously in hvm_hap_nested_page_fault(), put_gfn() was moved
before the handling of mmio, due to a deadlock risk between the p2m
lock and the event lock(in commit 77b8dfe). Later, a per-event channel
lock was introduced in commit de6acb7, to send events. So we do not
need to worry about the deadlock issue.
Signed-off-by: Yu Zhang <yu.c.zh...@linux.intel.com>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
However, shouldn't this go _before_ what is now patch 1?
Yes. This should be the patch 1/4. Thanks! :)
Yu
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