linux-kernel - [RFC PATCH v2 33/38] KVM: arm64: Emulate appropriate VM control system registers

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Message-Id: <1500397144-16232-34-git-send-email-jintack.lim@linaro.org>
Date:   Tue, 18 Jul 2017 11:58:59 -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 33/38] KVM: arm64: Emulate appropriate VM control system registers

Now that the virtual EL2 can access EL2 register states via EL1
registers, we need to consider it when selecting the register to
emulate.

Signed-off-by: Jintack Lim <jintack.lim@...aro.org>
---
 arch/arm64/kvm/sys_regs.c | 46 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 44 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 79980be..910b50d 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -110,6 +110,31 @@ static bool access_dcsw(struct kvm_vcpu *vcpu,
 	return true;
 }
 
+struct el1_el2_map {
+	int	el1;
+	int	el2;
+};
+
+static const struct el1_el2_map vm_map[] = {
+	{SCTLR_EL1, SCTLR_EL2},
+	{TTBR0_EL1, TTBR0_EL2},
+	{TTBR1_EL1, TTBR1_EL2},
+	{TCR_EL1, TCR_EL2},
+	{ESR_EL1, ESR_EL2},
+	{FAR_EL1, FAR_EL2},
+	{AFSR0_EL1, AFSR0_EL2},
+	{AFSR1_EL1, AFSR1_EL2},
+	{MAIR_EL1, MAIR_EL2},
+	{AMAIR_EL1, AMAIR_EL2},
+	{CONTEXTIDR_EL1, CONTEXTIDR_EL2},
+};
+
+static inline bool el12_reg(struct sys_reg_params *p)
+{
+	/* All *_EL12 registers have Op1=5. */
+	return (p->Op1 == 5);
+}
+
 /*
  * Generic accessor for VM registers. Only called as long as HCR_TVM
  * is set. If the guest enables the MMU, we stop trapping the VM
@@ -120,16 +145,33 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu,
 			  const struct sys_reg_desc *r)
 {
 	bool was_enabled = vcpu_has_cache_enabled(vcpu);
+	u64 *sysreg = &vcpu_sys_reg(vcpu, r->reg);
+	int i;
+	const struct el1_el2_map *map;
+
+	/*
+	 * Redirect EL1 register accesses to the corresponding EL2 registers if
+	 * they are meant to access EL2 registers.
+	 */
+	if (vcpu_el2_e2h_is_set(vcpu) && !el12_reg(p)) {
+		for (i = 0; i < ARRAY_SIZE(vm_map); i++) {
+			map = &vm_map[i];
+			if (map->el1 == r->reg) {
+				sysreg = &vcpu_sys_reg(vcpu, map->el2);
+				break;
+			}
+		}
+	}
 
 	BUG_ON(!vcpu_mode_el2(vcpu) && !p->is_write);
 
 	if (!p->is_write) {
-		p->regval = vcpu_sys_reg(vcpu, r->reg);
+		p->regval = *sysreg;
 		return true;
 	}
 
 	if (!p->is_aarch32) {
-		vcpu_sys_reg(vcpu, r->reg) = p->regval;
+		*sysreg = p->regval;
 	} else {
 		if (!p->is_32bit)
 			vcpu_cp15_64_high(vcpu, r->reg) = upper_32_bits(p->regval);
-- 
1.9.1