unimore/kernel-hacking-2024-linux-steffo
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vfio/ccw: identify CCW data addresses as physical

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The CCW data address created by vfio-ccw is that of an IDAL
built by this code. Since this address is used by real hardware,
it should be a physical address rather than a virtual one.
Let's clarify it as such in the ORB.

Similarly, once the I/O has completed the memory for that IDAL
needs to be released, so convert the CCW data address back to
a virtual address so that kfree() can process it.

Note: this currently doesn't fix a real bug, since virtual
addresses are identical to physical ones.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Link: https://lore.kernel.org/r/20221121165836.283781-3-farman@linux.ibm.com
This commit is contained in:
Eric Farman 2022-11-21 17:58:36 +01:00 committed by Alexander Gordeev
parent 21c7996917
commit 5de2322d7b
1 changed files with 2 additions and 2 deletions
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4
drivers/s390/cio/vfio_ccw_cp.c
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@ -394,7 +394,7 @@ static void ccwchain_cda_free(struct ccwchain *chain, int idx)
if (ccw_is_tic(ccw))
return;
kfree((void *)(u64)ccw->cda);
kfree(phys_to_virt(ccw->cda));
}
/**
@ -845,7 +845,7 @@ union orb *cp_get_orb(struct channel_program *cp, u32 intparm, u8 lpm)
chain = list_first_entry(&cp->ccwchain_list, struct ccwchain, next);
cpa = chain->ch_ccw;
orb->cmd.cpa = (__u32) __pa(cpa);
orb->cmd.cpa = (__u32)virt_to_phys(cpa);
return orb;
}