linux-kernel - [RFC PATCH v2 38/38] KVM: arm64: Respect the virtual CPTR

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Date:   Tue, 18 Jul 2017 11:59:04 -0500
From:   Jintack Lim <jintack.lim@...aro.org>
To:     kvmarm@...ts.cs.columbia.edu, christoffer.dall@...aro.org,
        marc.zyngier@....com
Cc:     corbet@....net, pbonzini@...hat.com, rkrcmar@...hat.com,
        linux@...linux.org.uk, catalin.marinas@....com,
        will.deacon@....com, akpm@...ux-foundation.org, mchehab@...nel.org,
        cov@...eaurora.org, daniel.lezcano@...aro.org,
        david.daney@...ium.com, mark.rutland@....com,
        suzuki.poulose@....com, stefan@...lo-penguin.com,
        andy.gross@...aro.org, wcohen@...hat.com,
        ard.biesheuvel@...aro.org, shankerd@...eaurora.org,
        vladimir.murzin@....com, james.morse@....com,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Jintack Lim <jintack.lim@...aro.org>
Subject: [RFC PATCH v2 38/38] KVM: arm64: Respect the virtual CPTR_EL2.TCPAC setting

Forward CPACR_EL1 traps to the virtual EL2 if virtual CPTR_EL2 is
configured to trap CPACR_EL1 accesses from EL1.

This is for recursive nested virtualization.

Signed-off-by: Jintack Lim <jintack.lim@...aro.org>
---
 arch/arm64/kvm/sys_regs.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 6f67666..ba2966d 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1091,6 +1091,11 @@ static bool access_cpacr(struct kvm_vcpu *vcpu,
 	if (el12_reg(p) && forward_nv_traps(vcpu))
 		return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
 
+	/* Forward this trap to the virtual EL2 if CPTR_EL2.TCPAC is set*/
+	if (!el12_reg(p) && !vcpu_mode_el2(vcpu) &&
+	    (vcpu_sys_reg(vcpu, CPTR_EL2) & CPTR_EL2_TCPAC))
+		return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
+
 	/*
 	 * When the virtual HCR_EL2.E2H == 1, an access to CPACR_EL1
 	 * in the virtual EL2 is to access CPTR_EL2.
-- 
1.9.1