Thread (127 messages) 127 messages, 11 authors, 2017-12-06
STALE3106d REVIEWED: 1 (0M)

[PATCH 03/37] KVM: arm64: Move HCR_INT_OVERRIDE to default HCR_EL2 guest flag

From: Marc Zyngier <hidden>
Date: 2017-10-12 16:20:49
Also in: kvm, kvmarm

On 12/10/17 11:41, Christoffer Dall wrote:
quoted hunk ↗ jump to hunk
From: Shih-Wei Li <redacted>

We always set the IMO and FMO bits in the HCR_EL2 when running the
guest, regardless if we use the vgic or not.  By moving these flags to
HCR_GUEST_FLAGS we can avoid one of the extra save/restore operations of
HCR_EL2 in the world switch code, and we can also soon get rid of the
other one.

Signed-off-by: Shih-Wei Li <redacted>
Signed-off-by: Christoffer Dall <redacted>
---
 arch/arm64/include/asm/kvm_arm.h | 4 ++--
 arch/arm64/kvm/hyp/switch.c      | 3 ---
 2 files changed, 2 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index 61d694c..e67e279 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -79,9 +79,9 @@
  */
 #define HCR_GUEST_FLAGS (HCR_TSC | HCR_TSW | HCR_TWE | HCR_TWI | HCR_VM | \
 			 HCR_TVM | HCR_BSU_IS | HCR_FB | HCR_TAC | \
-			 HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW)
+			 HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW | \
+			 HCR_FMO | HCR_IMO)
 #define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF)
-#define HCR_INT_OVERRIDE   (HCR_FMO | HCR_IMO)
 #define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H)
 
 /* TCR_EL2 Registers bits */
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index a50ddf3..bcf1a79 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -164,8 +164,6 @@ static void __hyp_text __vgic_save_state(struct kvm_vcpu *vcpu)
 		__vgic_v3_save_state(vcpu);
 	else
 		__vgic_v2_save_state(vcpu);
-
-	write_sysreg(read_sysreg(hcr_el2) & ~HCR_INT_OVERRIDE, hcr_el2);
 }
 
 static void __hyp_text __vgic_restore_state(struct kvm_vcpu *vcpu)
@@ -173,7 +171,6 @@ static void __hyp_text __vgic_restore_state(struct kvm_vcpu *vcpu)
 	u64 val;
 
 	val = read_sysreg(hcr_el2);
-	val |= 	HCR_INT_OVERRIDE;
 	val |= vcpu->arch.irq_lines;
 	write_sysreg(val, hcr_el2);
 
To expand on why this is actually safe: IMO/FMO control both taking the
interrupts to EL2 and remapping ICC_*_EL1 to ICV_*_EL1 executed at EL1.
As long as we ensure that these bits are clear when returning to the EL1
host, we're OK.

Reviewed-by: Marc Zyngier <redacted>

	M.
-- 
Jazz is not dead. It just smells funny...
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