Hello James,
On 3/6/2017 3:28 AM, James Morse wrote:
On 28/02/17 19:43, Baicar, Tyler wrote:
On 2/24/2017 3:42 AM, James Morse wrote:
On 21/02/17 21:22, Tyler Baicar wrote:
Currently external aborts are unsupported by the guest abort
handling. Add handling for SEAs so that the host kernel reports
SEAs which occur in the guest kernel.
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index b2d57fc..403277b 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -602,6 +602,24 @@ static const char *fault_name(unsigned int esr)
}
/*
+ * Handle Synchronous External Aborts that occur in a guest kernel.
+ */
+int handle_guest_sea(unsigned long addr, unsigned int esr)
+{
+ if(IS_ENABLED(HAVE_ACPI_APEI_SEA)) {
+ nmi_enter();
+ ghes_notify_sea();
+ nmi_exit();
This nmi stuff was needed for synchronous aborts that may have interrupted
APEI's interrupts-masked code. We want to avoid trying to take the same set of
locks, hence taking the in_nmi() path through APEI. Here we know we interrupted
a guest, so there is no risk that we have interrupted APEI on the host.
ghes_notify_sea() can safely take the normal path.
Makes sense, I can remove the nmi_* calls here.
Just occurs to me: if we do this we need to add the rcu_read_lock() in
ghes_notify_sea() as its not protected by the rcu/nmi weirdness.
True, would you suggest leaving these nmi_* calls or adding the rcu_*
calls? And since that's only needed for this KVM case, shouldn't the
rcu_* calls just replace the nmi_* calls here (outside of ghes_notify_sea)?
Thanks,
Tyler
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