Patchwork [03/13] arm64: KVM: reset E2PB correctly in MDCR_EL2 when exiting the guest(VHE)

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Submitter Sudeep Holla
Date Feb. 28, 2019, 4:07 p.m.
Message ID <20190228160737.3323-4-sudeep.holla@arm.com>
Download mbox | patch
Permalink /patch/738321/
State New
Headers show

Comments

Sudeep Holla - Feb. 28, 2019, 4:07 p.m.
On VHE systems, the reset value for MDCR_EL2.E2PB=b00 which defaults
to profiling buffer using the EL2 stage 1 translations. However if the
guest are allowed to use profiling buffers changing E2PB settings, we
need to ensure we resume back MDCR_EL2.E2PB=b00. Currently we just
do bitwise '&' with MDCR_EL2_E2PB_MASK which will retain the value.

So fix it by clearing all the bits in E2PB.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
 arch/arm64/kvm/hyp/switch.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

Patch

diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 421ebf6f7086..08e2a01188ac 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -198,9 +198,7 @@  void deactivate_traps_vhe_put(void)
 {
 	u64 mdcr_el2 = read_sysreg(mdcr_el2);
 
-	mdcr_el2 &= MDCR_EL2_HPMN_MASK |
-		    MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT |
-		    MDCR_EL2_TPMS;
+	mdcr_el2 &= MDCR_EL2_HPMN_MASK | MDCR_EL2_TPMS;
 
 	write_sysreg(mdcr_el2, mdcr_el2);