[PATCH 3/3] KVM: arm64: Add emulation for 32bit guests accessing ACTLR2

[James Morse <james.morse@arm.com>]

ACTLR_EL1 is a 64bit register while the 32bit ACTLR is obviously 32bit.
For 32bit software, the extra bits are accessible via ACTLR2... which
KVM doesn't emulate.

Signed-off-by: James Morse <james.morse@arm.com>
---
I'm not convinced this is endian safe, but it does match what
kvm_inject_undef32() do.

The alternative would be to always read the 64bit value, and generate
the 32bit offets like access_vm_reg() does.

 arch/arm64/include/asm/kvm_host.h    |  1 +
 arch/arm64/kvm/sys_regs_generic_v8.c | 16 +++++++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 32c8a675e5a4..5b7538663a8e 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -185,6 +185,7 @@ enum vcpu_sysreg {
 #define c0_CSSELR	(CSSELR_EL1 * 2)/* Cache Size Selection Register */
 #define c1_SCTLR	(SCTLR_EL1 * 2)	/* System Control Register */
 #define c1_ACTLR	(ACTLR_EL1 * 2)	/* Auxiliary Control Register */
+#define c1_ACTLR2	(c1_ACTLR + 1)	/* ACTLR top 32 bits */
 #define c1_CPACR	(CPACR_EL1 * 2)	/* Coprocessor Access Control */
 #define c2_TTBR0	(TTBR0_EL1 * 2)	/* Translation Table Base Register 0 */
 #define c2_TTBR0_high	(c2_TTBR0 + 1)	/* TTBR0 top 32 bits */
diff --git a/arch/arm64/kvm/sys_regs_generic_v8.c b/arch/arm64/kvm/sys_regs_generic_v8.c
index 9cb6b4c8355a..ed77bbb48e64 100644
--- a/arch/arm64/kvm/sys_regs_generic_v8.c
+++ b/arch/arm64/kvm/sys_regs_generic_v8.c
@@ -30,6 +30,18 @@ static bool access_actlr(struct kvm_vcpu *vcpu,
 	return true;
 }
 
+static bool access_cp15_actlr(struct kvm_vcpu *vcpu,
+			      struct sys_reg_params *p,
+			      const struct sys_reg_desc *r)
+{
+	if (p->is_write)
+		return ignore_write(vcpu, p);
+
+	p->regval = vcpu_cp15(vcpu, r->reg);
+	return true;
+
+}
+
 static void reset_actlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 {
 	__vcpu_sys_reg(vcpu, ACTLR_EL1) = read_sysreg(actlr_el1);
@@ -46,7 +58,9 @@ static const struct sys_reg_desc genericv8_sys_regs[] = {
 static const struct sys_reg_desc genericv8_cp15_regs[] = {
 	/* ACTLR */
 	{ Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b001),
-	  access_actlr },
+	  access_cp15_actlr, NULL, c1_ACTLR },
+	{ Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b011),
+	  access_cp15_actlr, NULL, c1_ACTLR2 },
 };
 
 static struct kvm_sys_reg_target_table genericv8_target_table = {
-- 
2.20.1


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