| Message ID | 20160620064048.19333-1-ruscur@russell.cc |
|---|---|
| State | Accepted |
| Headers | show |
Russell Currey <ruscur@russell.cc> writes: > NPU freeze injection works by performing an invalid MMIO read on the NPU > device BAR. If the BAR isn't enabled, which is the case when the > appropriate driver isn't loaded, this checkstops the machine. > > Work around this by making sure the BAR is enabled before performing the > read. The idea of an error inject doing anything other than an error > inject isn't great, but it's better than unintentionally crashing your > machine. > > Also, fix the comment incorrectly stating the operation was a write > instead of a read. > > Signed-off-by: Russell Currey <ruscur@russell.cc> > --- > hw/npu.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) Looks good, merged to master as of 0f23e5b
diff --git a/hw/npu.c b/hw/npu.c index e444b96..834b3e3 100644 --- a/hw/npu.c +++ b/hw/npu.c @@ -1118,7 +1118,10 @@ static int64_t npu_err_inject(struct phb *phb, uint32_t pe_num, /* Emulate fence mode. */ p->fenced = true; } else { - /* Cause a freeze with an invalid MMIO write. */ + /* Cause a freeze with an invalid MMIO read. If the BAR is not + * enabled, this will checkstop the machine. + */ + npu_dev_bar_update(p->chip_id, &dev->bar, true); in_be64((void *)dev->bar.base); }
NPU freeze injection works by performing an invalid MMIO read on the NPU device BAR. If the BAR isn't enabled, which is the case when the appropriate driver isn't loaded, this checkstops the machine. Work around this by making sure the BAR is enabled before performing the read. The idea of an error inject doing anything other than an error inject isn't great, but it's better than unintentionally crashing your machine. Also, fix the comment incorrectly stating the operation was a write instead of a read. Signed-off-by: Russell Currey <ruscur@russell.cc> --- hw/npu.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)