diff mbox series

[v2,07/20] KVM: arm64: nVHE: Don't consume host SErrors with ESB

Message ID 20200820103446.959000-8-ascull@google.com (mailing list archive)
State New, archived
Headers show
Series Introduce separate nVHE hyp context | expand

Commit Message

Andrew Scull Aug. 20, 2020, 10:34 a.m. UTC 
The ESB at the start of the host vector may cause SErrors to be consumed
to DISR_EL1. However, this is not checked for the host so the SError
could go unhandled.

Remove the ESB so that SErrors are not consumed but are instead left
pending for the host to consume. __guest_enter already defers entry into
a guest if there are any SErrors pending.

Fixes: 0e5b9c085dce ("KVM: arm64: Consume pending SError as early as possible")
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Andrew Scull <ascull@google.com>
---
 arch/arm64/kvm/hyp/nvhe/host.S | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
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Patch

diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S
index 9c96b9a3b71d..5a7380c342c8 100644
--- a/arch/arm64/kvm/hyp/nvhe/host.S
+++ b/arch/arm64/kvm/hyp/nvhe/host.S
@@ -24,7 +24,6 @@  SYM_FUNC_END(__hyp_do_panic)
 
 .macro valid_host_el1_sync_vect
 	.align 7
-	esb
 	stp	x0, x1, [sp, #-16]!
 
 	mrs	x0, esr_el2
@@ -77,6 +76,11 @@  SYM_FUNC_END(__hyp_do_panic)
 .endm
 
 /*
+ * The host vector does not use an ESB instruction in order to avoid consuming
+ * SErrors that should only be consumed by the host. Guest entry is deferred by
+ * __guest_enter if there are any pending asynchronous exceptions so hyp will
+ * always return to the host without having consumerd host SErrors.
+ *
  * CONFIG_KVM_INDIRECT_VECTORS is not applied to the host vector because the
  * host already knows the address of hyp by virtue of loading it there.
  */