linux-kernel - [RFC 06/55] KVM: arm64: Add EL2 execution context for nesting

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Date:   Mon,  9 Jan 2017 01:24:02 -0500
From:   Jintack Lim <jintack@...columbia.edu>
To:     christoffer.dall@...aro.org, marc.zyngier@....com,
        pbonzini@...hat.com, rkrcmar@...hat.com, linux@...linux.org.uk,
        catalin.marinas@....com, will.deacon@....com,
        vladimir.murzin@....com, suzuki.poulose@....com,
        mark.rutland@....com, james.morse@....com,
        lorenzo.pieralisi@....com, kevin.brodsky@....com,
        wcohen@...hat.com, shankerd@...eaurora.org, geoff@...radead.org,
        andre.przywara@....com, eric.auger@...hat.com,
        anna-maria@...utronix.de, shihwei@...columbia.edu,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     jintack@...columbia.edu
Subject: [RFC 06/55] KVM: arm64: Add EL2 execution context for nesting

With the nested virtualization support, the context of the guest
includes EL2 register states. The host manages a set of virtual EL2
registers.  In addition to that, the guest hypervisor supposed to run in
EL2 is now deprivilaged and runs in EL1. So, the host also manages a set
of shadow system registers to be able to run the guest hypervisor in
EL1.

Signed-off-by: Jintack Lim <jintack@...columbia.edu>
Signed-off-by: Christoffer Dall <christoffer.dall@...aro.org>
---
 arch/arm64/include/asm/kvm_host.h | 54 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index c0c8b02..ed78d73 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -146,6 +146,42 @@ enum vcpu_sysreg {
 	NR_SYS_REGS	/* Nothing after this line! */
 };
 
+enum el2_regs {
+	ELR_EL2,
+	SPSR_EL2,
+	SP_EL2,
+	AMAIR_EL2,
+	MAIR_EL2,
+	TCR_EL2,
+	TTBR0_EL2,
+	VTCR_EL2,
+	VTTBR_EL2,
+	VMPIDR_EL2,
+	VPIDR_EL2,      /* 10 */
+	MDCR_EL2,
+	CNTHCTL_EL2,
+	CNTHP_CTL_EL2,
+	CNTHP_CVAL_EL2,
+	CNTHP_TVAL_EL2,
+	CNTVOFF_EL2,
+	ACTLR_EL2,
+	AFSR0_EL2,
+	AFSR1_EL2,
+	CPTR_EL2,       /* 20 */
+	ESR_EL2,
+	FAR_EL2,
+	HACR_EL2,
+	HCR_EL2,
+	HPFAR_EL2,
+	HSTR_EL2,
+	RMR_EL2,
+	RVBAR_EL2,
+	SCTLR_EL2,
+	TPIDR_EL2,      /* 30 */
+	VBAR_EL2,
+	NR_EL2_REGS     /* Nothing after this line! */
+};
+
 /* 32bit mapping */
 #define c0_MPIDR	(MPIDR_EL1 * 2)	/* MultiProcessor ID Register */
 #define c0_CSSELR	(CSSELR_EL1 * 2)/* Cache Size Selection Register */
@@ -193,6 +229,23 @@ struct kvm_cpu_context {
 		u64 sys_regs[NR_SYS_REGS];
 		u32 copro[NR_COPRO_REGS];
 	};
+
+	u64 el2_regs[NR_EL2_REGS];         /* only used for nesting */
+	u64 shadow_sys_regs[NR_SYS_REGS];  /* only used for virtual EL2 */
+
+	/*
+	 * hw_* will be used when switching to a VM. They point to either
+	 * the virtual EL2 or EL1/EL0 context depending on vcpu mode.
+	 */
+
+	/* pointing shadow_sys_regs or sys_regs */
+	u64 *hw_sys_regs;
+
+	/* copy of either gp_regs.sp_el1 or el2_regs[SP_EL2] */
+	u64 hw_sp_el1;
+
+	/* pstate written to SPSR_EL2 */
+	u64 hw_pstate;
 };
 
 typedef struct kvm_cpu_context kvm_cpu_context_t;
@@ -277,6 +330,7 @@ struct kvm_vcpu_arch {
 
 #define vcpu_gp_regs(v)		(&(v)->arch.ctxt.gp_regs)
 #define vcpu_sys_reg(v,r)	((v)->arch.ctxt.sys_regs[(r)])
+#define vcpu_el2_reg(v, r)	((v)->arch.ctxt.el2_regs[(r)])
 /*
  * CP14 and CP15 live in the same array, as they are backed by the
  * same system registers.
-- 
1.9.1