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authorJames Morse <james.morse@arm.com>2019-06-18 18:17:35 +0300
committerMarc Zyngier <marc.zyngier@arm.com>2019-07-05 15:03:29 +0300
commit5d994374e872bef1bba25c80950af6a77ea470e1 (patch)
treebb9bd1f1f0ad323a6c6aaa5d3652b73effc917d9 /arch/arm64/kvm
parent3dbf100b0b10e91d65bd83b91cee3ef61f1b96c4 (diff)
downloadlinux-5d994374e872bef1bba25c80950af6a77ea470e1.tar.xz
KVM: arm64: Make indirect vectors preamble behaviour symmetric
The KVM indirect vectors support is a little complicated. Different CPUs may use different exception vectors for KVM that are generated at boot. Adding new instructions involves checking all the possible combinations do the right thing. To make changes here easier to review lets state what we expect of the preamble: 1. The first vector run, must always run the preamble. 2. Patching the head or tail of the vector shouldn't remove preamble instructions. Today, this is easy as we only have one instruction in the preamble. Change the unpatched tail of the indirect vector so that it always runs this, regardless of patching. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm64/kvm')
-rw-r--r--arch/arm64/kvm/hyp/hyp-entry.S6
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 318a2f3996fc..a911b8ffc0f3 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -275,7 +275,7 @@ ENDPROC(__kvm_hyp_vector)
/*
* The default sequence is to directly branch to the KVM vectors,
* using the computed offset. This applies for VHE as well as
- * !ARM64_HARDEN_EL2_VECTORS.
+ * !ARM64_HARDEN_EL2_VECTORS. The first vector must always run the preamble.
*
* For ARM64_HARDEN_EL2_VECTORS configurations, this gets replaced
* with:
@@ -291,8 +291,8 @@ ENDPROC(__kvm_hyp_vector)
* See kvm_patch_vector_branch for details.
*/
alternative_cb kvm_patch_vector_branch
- b __kvm_hyp_vector + (1b - 0b)
- nop
+ stp x0, x1, [sp, #-16]!
+ b __kvm_hyp_vector + (1b - 0b + KVM_VECTOR_PREAMBLE)
nop
nop
nop