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

Jintack Lim
2017-01-09T06:24:02Z

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@cs.columbia.edu>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.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