1 files changed, 138 insertions, 34 deletions

diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index 2c17afd2be96..b3894df6bf1a 100644
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -19,32 +19,43 @@
 #include <linux/kvm_host.h>
 
 #include <asm/kvm_asm.h>
+#include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>
 
-/* Yes, this does nothing, on purpose */
-static void __hyp_text __sysreg_do_nothing(struct kvm_cpu_context *ctxt) { }
-
 /*
  * Non-VHE: Both host and guest must save everything.
  *
- * VHE: Host must save tpidr*_el0, actlr_el1, mdscr_el1, sp_el0,
- * and guest must save everything.
+ * VHE: Host and guest must save mdscr_el1 and sp_el0 (and the PC and pstate,
+ * which are handled as part of the el2 return state) on every switch.
+ * tpidr_el0 and tpidrro_el0 only need to be switched when going
+ * to host userspace or a different VCPU.  EL1 registers only need to be
+ * switched when potentially going to run a different VCPU.  The latter two
+ * classes are handled as part of kvm_arch_vcpu_load and kvm_arch_vcpu_put.
  */
 
 static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
 {
-	ctxt->sys_regs[ACTLR_EL1]	= read_sysreg(actlr_el1);
-	ctxt->sys_regs[TPIDR_EL0]	= read_sysreg(tpidr_el0);
-	ctxt->sys_regs[TPIDRRO_EL0]	= read_sysreg(tpidrro_el0);
 	ctxt->sys_regs[MDSCR_EL1]	= read_sysreg(mdscr_el1);
+
+	/*
+	 * The host arm64 Linux uses sp_el0 to point to 'current' and it must
+	 * therefore be saved/restored on every entry/exit to/from the guest.
+	 */
 	ctxt->gp_regs.regs.sp		= read_sysreg(sp_el0);
 }
 
-static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
+static void __hyp_text __sysreg_save_user_state(struct kvm_cpu_context *ctxt)
+{
+	ctxt->sys_regs[TPIDR_EL0]	= read_sysreg(tpidr_el0);
+	ctxt->sys_regs[TPIDRRO_EL0]	= read_sysreg(tpidrro_el0);
+}
+
+static void __hyp_text __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
 {
 	ctxt->sys_regs[MPIDR_EL1]	= read_sysreg(vmpidr_el2);
 	ctxt->sys_regs[CSSELR_EL1]	= read_sysreg(csselr_el1);
 	ctxt->sys_regs[SCTLR_EL1]	= read_sysreg_el1(sctlr);
+	ctxt->sys_regs[ACTLR_EL1]	= read_sysreg(actlr_el1);
 	ctxt->sys_regs[CPACR_EL1]	= read_sysreg_el1(cpacr);
 	ctxt->sys_regs[TTBR0_EL1]	= read_sysreg_el1(ttbr0);
 	ctxt->sys_regs[TTBR1_EL1]	= read_sysreg_el1(ttbr1);
@@ -64,6 +75,10 @@ static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
 	ctxt->gp_regs.sp_el1		= read_sysreg(sp_el1);
 	ctxt->gp_regs.elr_el1		= read_sysreg_el1(elr);
 	ctxt->gp_regs.spsr[KVM_SPSR_EL1]= read_sysreg_el1(spsr);
+}
+
+static void __hyp_text __sysreg_save_el2_return_state(struct kvm_cpu_context *ctxt)
+{
 	ctxt->gp_regs.regs.pc		= read_sysreg_el2(elr);
 	ctxt->gp_regs.regs.pstate	= read_sysreg_el2(spsr);
 
@@ -71,36 +86,48 @@ static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
 		ctxt->sys_regs[DISR_EL1] = read_sysreg_s(SYS_VDISR_EL2);
 }
 
-static hyp_alternate_select(__sysreg_call_save_host_state,
-			    __sysreg_save_state, __sysreg_do_nothing,
-			    ARM64_HAS_VIRT_HOST_EXTN);
+void __hyp_text __sysreg_save_state_nvhe(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_save_el1_state(ctxt);
+	__sysreg_save_common_state(ctxt);
+	__sysreg_save_user_state(ctxt);
+	__sysreg_save_el2_return_state(ctxt);
+}
 
-void __hyp_text __sysreg_save_host_state(struct kvm_cpu_context *ctxt)
+void sysreg_save_host_state_vhe(struct kvm_cpu_context *ctxt)
 {
-	__sysreg_call_save_host_state()(ctxt);
 	__sysreg_save_common_state(ctxt);
 }
 
-void __hyp_text __sysreg_save_guest_state(struct kvm_cpu_context *ctxt)
+void sysreg_save_guest_state_vhe(struct kvm_cpu_context *ctxt)
 {
-	__sysreg_save_state(ctxt);
 	__sysreg_save_common_state(ctxt);
+	__sysreg_save_el2_return_state(ctxt);
 }
 
 static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctxt)
 {
-	write_sysreg(ctxt->sys_regs[ACTLR_EL1],	  actlr_el1);
-	write_sysreg(ctxt->sys_regs[TPIDR_EL0],	  tpidr_el0);
-	write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
 	write_sysreg(ctxt->sys_regs[MDSCR_EL1],	  mdscr_el1);
+
+	/*
+	 * The host arm64 Linux uses sp_el0 to point to 'current' and it must
+	 * therefore be saved/restored on every entry/exit to/from the guest.
+	 */
 	write_sysreg(ctxt->gp_regs.regs.sp,	  sp_el0);
 }
 
-static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
+static void __hyp_text __sysreg_restore_user_state(struct kvm_cpu_context *ctxt)
+{
+	write_sysreg(ctxt->sys_regs[TPIDR_EL0],	  	tpidr_el0);
+	write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], 	tpidrro_el0);
+}
+
+static void __hyp_text __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
 {
 	write_sysreg(ctxt->sys_regs[MPIDR_EL1],		vmpidr_el2);
 	write_sysreg(ctxt->sys_regs[CSSELR_EL1],	csselr_el1);
 	write_sysreg_el1(ctxt->sys_regs[SCTLR_EL1],	sctlr);
+	write_sysreg(ctxt->sys_regs[ACTLR_EL1],	  	actlr_el1);
 	write_sysreg_el1(ctxt->sys_regs[CPACR_EL1],	cpacr);
 	write_sysreg_el1(ctxt->sys_regs[TTBR0_EL1],	ttbr0);
 	write_sysreg_el1(ctxt->sys_regs[TTBR1_EL1],	ttbr1);
@@ -120,6 +147,11 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
 	write_sysreg(ctxt->gp_regs.sp_el1,		sp_el1);
 	write_sysreg_el1(ctxt->gp_regs.elr_el1,		elr);
 	write_sysreg_el1(ctxt->gp_regs.spsr[KVM_SPSR_EL1],spsr);
+}
+
+static void __hyp_text
+__sysreg_restore_el2_return_state(struct kvm_cpu_context *ctxt)
+{
 	write_sysreg_el2(ctxt->gp_regs.regs.pc,		elr);
 	write_sysreg_el2(ctxt->gp_regs.regs.pstate,	spsr);
 
@@ -127,27 +159,30 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
 		write_sysreg_s(ctxt->sys_regs[DISR_EL1], SYS_VDISR_EL2);
 }
 
-static hyp_alternate_select(__sysreg_call_restore_host_state,
-			    __sysreg_restore_state, __sysreg_do_nothing,
-			    ARM64_HAS_VIRT_HOST_EXTN);
+void __hyp_text __sysreg_restore_state_nvhe(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_restore_el1_state(ctxt);
+	__sysreg_restore_common_state(ctxt);
+	__sysreg_restore_user_state(ctxt);
+	__sysreg_restore_el2_return_state(ctxt);
+}
 
-void __hyp_text __sysreg_restore_host_state(struct kvm_cpu_context *ctxt)
+void sysreg_restore_host_state_vhe(struct kvm_cpu_context *ctxt)
 {
-	__sysreg_call_restore_host_state()(ctxt);
 	__sysreg_restore_common_state(ctxt);
 }
 
-void __hyp_text __sysreg_restore_guest_state(struct kvm_cpu_context *ctxt)
+void sysreg_restore_guest_state_vhe(struct kvm_cpu_context *ctxt)
 {
-	__sysreg_restore_state(ctxt);
 	__sysreg_restore_common_state(ctxt);
+	__sysreg_restore_el2_return_state(ctxt);
 }
 
 void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
 {
 	u64 *spsr, *sysreg;
 
-	if (read_sysreg(hcr_el2) & HCR_RW)
+	if (!vcpu_el1_is_32bit(vcpu))
 		return;
 
 	spsr = vcpu->arch.ctxt.gp_regs.spsr;
@@ -161,10 +196,7 @@ void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
 	sysreg[DACR32_EL2] = read_sysreg(dacr32_el2);
 	sysreg[IFSR32_EL2] = read_sysreg(ifsr32_el2);
 
-	if (__fpsimd_enabled())
-		sysreg[FPEXC32_EL2] = read_sysreg(fpexc32_el2);
-
-	if (vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY)
+	if (has_vhe() || vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY)
 		sysreg[DBGVCR32_EL2] = read_sysreg(dbgvcr32_el2);
 }
 
@@ -172,7 +204,7 @@ void __hyp_text __sysreg32_restore_state(struct kvm_vcpu *vcpu)
 {
 	u64 *spsr, *sysreg;
 
-	if (read_sysreg(hcr_el2) & HCR_RW)
+	if (!vcpu_el1_is_32bit(vcpu))
 		return;
 
 	spsr = vcpu->arch.ctxt.gp_regs.spsr;
@@ -186,6 +218,78 @@ void __hyp_text __sysreg32_restore_state(struct kvm_vcpu *vcpu)
 	write_sysreg(sysreg[DACR32_EL2], dacr32_el2);
 	write_sysreg(sysreg[IFSR32_EL2], ifsr32_el2);
 
-	if (vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY)
+	if (has_vhe() || vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY)
 		write_sysreg(sysreg[DBGVCR32_EL2], dbgvcr32_el2);
 }
+
+/**
+ * kvm_vcpu_load_sysregs - Load guest system registers to the physical CPU
+ *
+ * @vcpu: The VCPU pointer
+ *
+ * Load system registers that do not affect the host's execution, for
+ * example EL1 system registers on a VHE system where the host kernel
+ * runs at EL2.  This function is called from KVM's vcpu_load() function
+ * and loading system register state early avoids having to load them on
+ * every entry to the VM.
+ */
+void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu)
+{
+	struct kvm_cpu_context *host_ctxt = vcpu->arch.host_cpu_context;
+	struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
+
+	if (!has_vhe())
+		return;
+
+	__sysreg_save_user_state(host_ctxt);
+
+	/*
+	 * Load guest EL1 and user state
+	 *
+	 * We must restore the 32-bit state before the sysregs, thanks
+	 * to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
+	 */
+	__sysreg32_restore_state(vcpu);
+	__sysreg_restore_user_state(guest_ctxt);
+	__sysreg_restore_el1_state(guest_ctxt);
+
+	vcpu->arch.sysregs_loaded_on_cpu = true;
+
+	activate_traps_vhe_load(vcpu);
+}
+
+/**
+ * kvm_vcpu_put_sysregs - Restore host system registers to the physical CPU
+ *
+ * @vcpu: The VCPU pointer
+ *
+ * Save guest system registers that do not affect the host's execution, for
+ * example EL1 system registers on a VHE system where the host kernel
+ * runs at EL2.  This function is called from KVM's vcpu_put() function
+ * and deferring saving system register state until we're no longer running the
+ * VCPU avoids having to save them on every exit from the VM.
+ */
+void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu)
+{
+	struct kvm_cpu_context *host_ctxt = vcpu->arch.host_cpu_context;
+	struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
+
+	if (!has_vhe())
+		return;
+
+	deactivate_traps_vhe_put();
+
+	__sysreg_save_el1_state(guest_ctxt);
+	__sysreg_save_user_state(guest_ctxt);
+	__sysreg32_save_state(vcpu);
+
+	/* Restore host user state */
+	__sysreg_restore_user_state(host_ctxt);
+
+	vcpu->arch.sysregs_loaded_on_cpu = false;
+}
+
+void __hyp_text __kvm_set_tpidr_el2(u64 tpidr_el2)
+{
+	asm("msr tpidr_el2, %0": : "r" (tpidr_el2));
+}