arm64: KVM: Implement debug save/restore

Implement the debug save restore as a direct translation of
the assembly code version.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
index ec94200e1e509c4e95c3d8c01b63a8241df003c8..ec14cacc21a6df87078d7b0ef994d621ea0654c0 100644 (file)
--- a/arch/arm64/kvm/hyp/Makefile
+++ b/arch/arm64/kvm/hyp/Makefile
@@ -6,3 +6,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += vgic-v2-sr.o
 obj-$(CONFIG_KVM_ARM_HOST) += vgic-v3-sr.o
 obj-$(CONFIG_KVM_ARM_HOST) += timer-sr.o
 obj-$(CONFIG_KVM_ARM_HOST) += sysreg-sr.o
+obj-$(CONFIG_KVM_ARM_HOST) += debug-sr.o

diff --git a/arch/arm64/kvm/hyp/debug-sr.c b/arch/arm64/kvm/hyp/debug-sr.c
new file mode 100644 (file)
index 0000000..7848322
--- /dev/null
+++ b/arch/arm64/kvm/hyp/debug-sr.c
@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2015 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/compiler.h>
+#include <linux/kvm_host.h>
+
+#include <asm/kvm_mmu.h>
+
+#include "hyp.h"
+
+#define read_debug(r,n)                read_sysreg(r##n##_el1)
+#define write_debug(v,r,n)     write_sysreg(v, r##n##_el1)
+
+#define save_debug(ptr,reg,nr)                                         \
+       switch (nr) {                                                   \
+       case 15:        ptr[15] = read_debug(reg, 15);                  \
+       case 14:        ptr[14] = read_debug(reg, 14);                  \
+       case 13:        ptr[13] = read_debug(reg, 13);                  \
+       case 12:        ptr[12] = read_debug(reg, 12);                  \
+       case 11:        ptr[11] = read_debug(reg, 11);                  \
+       case 10:        ptr[10] = read_debug(reg, 10);                  \
+       case 9:         ptr[9] = read_debug(reg, 9);                    \
+       case 8:         ptr[8] = read_debug(reg, 8);                    \
+       case 7:         ptr[7] = read_debug(reg, 7);                    \
+       case 6:         ptr[6] = read_debug(reg, 6);                    \
+       case 5:         ptr[5] = read_debug(reg, 5);                    \
+       case 4:         ptr[4] = read_debug(reg, 4);                    \
+       case 3:         ptr[3] = read_debug(reg, 3);                    \
+       case 2:         ptr[2] = read_debug(reg, 2);                    \
+       case 1:         ptr[1] = read_debug(reg, 1);                    \
+       default:        ptr[0] = read_debug(reg, 0);                    \
+       }
+
+#define restore_debug(ptr,reg,nr)                                      \
+       switch (nr) {                                                   \
+       case 15:        write_debug(ptr[15], reg, 15);                  \
+       case 14:        write_debug(ptr[14], reg, 14);                  \
+       case 13:        write_debug(ptr[13], reg, 13);                  \
+       case 12:        write_debug(ptr[12], reg, 12);                  \
+       case 11:        write_debug(ptr[11], reg, 11);                  \
+       case 10:        write_debug(ptr[10], reg, 10);                  \
+       case 9:         write_debug(ptr[9], reg, 9);                    \
+       case 8:         write_debug(ptr[8], reg, 8);                    \
+       case 7:         write_debug(ptr[7], reg, 7);                    \
+       case 6:         write_debug(ptr[6], reg, 6);                    \
+       case 5:         write_debug(ptr[5], reg, 5);                    \
+       case 4:         write_debug(ptr[4], reg, 4);                    \
+       case 3:         write_debug(ptr[3], reg, 3);                    \
+       case 2:         write_debug(ptr[2], reg, 2);                    \
+       case 1:         write_debug(ptr[1], reg, 1);                    \
+       default:        write_debug(ptr[0], reg, 0);                    \
+       }
+
+void __hyp_text __debug_save_state(struct kvm_vcpu *vcpu,
+                                  struct kvm_guest_debug_arch *dbg,
+                                  struct kvm_cpu_context *ctxt)
+{
+       u64 aa64dfr0;
+       int brps, wrps;
+
+       if (!(vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY))
+               return;
+
+       aa64dfr0 = read_sysreg(id_aa64dfr0_el1);
+       brps = (aa64dfr0 >> 12) & 0xf;
+       wrps = (aa64dfr0 >> 20) & 0xf;
+
+       save_debug(dbg->dbg_bcr, dbgbcr, brps);
+       save_debug(dbg->dbg_bvr, dbgbvr, brps);
+       save_debug(dbg->dbg_wcr, dbgwcr, wrps);
+       save_debug(dbg->dbg_wvr, dbgwvr, wrps);
+
+       ctxt->sys_regs[MDCCINT_EL1] = read_sysreg(mdccint_el1);
+}
+
+void __hyp_text __debug_restore_state(struct kvm_vcpu *vcpu,
+                                     struct kvm_guest_debug_arch *dbg,
+                                     struct kvm_cpu_context *ctxt)
+{
+       u64 aa64dfr0;
+       int brps, wrps;
+
+       if (!(vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY))
+               return;
+
+       aa64dfr0 = read_sysreg(id_aa64dfr0_el1);
+
+       brps = (aa64dfr0 >> 12) & 0xf;
+       wrps = (aa64dfr0 >> 20) & 0xf;
+
+       restore_debug(dbg->dbg_bcr, dbgbcr, brps);
+       restore_debug(dbg->dbg_bvr, dbgbvr, brps);
+       restore_debug(dbg->dbg_wcr, dbgwcr, wrps);
+       restore_debug(dbg->dbg_wvr, dbgwvr, wrps);
+
+       write_sysreg(ctxt->sys_regs[MDCCINT_EL1], mdccint_el1);
+}
+
+void __hyp_text __debug_cond_save_host_state(struct kvm_vcpu *vcpu)
+{
+       /* If any of KDE, MDE or KVM_ARM64_DEBUG_DIRTY is set, perform
+        * a full save/restore cycle. */
+       if ((vcpu->arch.ctxt.sys_regs[MDSCR_EL1] & DBG_MDSCR_KDE) ||
+           (vcpu->arch.ctxt.sys_regs[MDSCR_EL1] & DBG_MDSCR_MDE))
+               vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
+
+       __debug_save_state(vcpu, &vcpu->arch.host_debug_state,
+                          kern_hyp_va(vcpu->arch.host_cpu_context));
+}
+
+void __hyp_text __debug_cond_restore_host_state(struct kvm_vcpu *vcpu)
+{
+       __debug_restore_state(vcpu, &vcpu->arch.host_debug_state,
+                             kern_hyp_va(vcpu->arch.host_cpu_context));
+
+       if (vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY)
+               vcpu->arch.debug_flags &= ~KVM_ARM64_DEBUG_DIRTY;
+}
+
+u32 __hyp_text __debug_read_mdcr_el2(void)
+{
+       return read_sysreg(mdcr_el2);
+}

diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h
index bffd30834eb8e2e56e14b90c87dcceb121635535..454e46f9c15ed808b4e3186d7160fc19a15053f7 100644 (file)
--- a/arch/arm64/kvm/hyp/hyp.h
+++ b/arch/arm64/kvm/hyp/hyp.h
@@ -43,5 +43,14 @@ void __sysreg_restore_state(struct kvm_cpu_context *ctxt);
 void __sysreg32_save_state(struct kvm_vcpu *vcpu);
 void __sysreg32_restore_state(struct kvm_vcpu *vcpu);
 
+void __debug_save_state(struct kvm_vcpu *vcpu,
+                       struct kvm_guest_debug_arch *dbg,
+                       struct kvm_cpu_context *ctxt);
+void __debug_restore_state(struct kvm_vcpu *vcpu,
+                          struct kvm_guest_debug_arch *dbg,
+                          struct kvm_cpu_context *ctxt);
+void __debug_cond_save_host_state(struct kvm_vcpu *vcpu);
+void __debug_cond_restore_host_state(struct kvm_vcpu *vcpu);
+
 #endif /* __ARM64_KVM_HYP_H__ */