On Fri, Jun 20, 2014 at 02:00:06PM +0100, Marc Zyngier wrote: > Implement switching of the debug registers. While the number > of registers is massive, CPUs usually don't implement them all > (A57 has 6 breakpoints and 4 watchpoints, which gives us a total > of 22 registers "only"). > > Also, we only save/restore them when MDSCR_EL1 has debug enabled, > or when we've flagged the debug registers as dirty. It means that > most of the time, we only save/restore MDSCR_EL1. > > Reviewed-by: Anup Patel <anup.patel@xxxxxxxxxx> > Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> > --- > arch/arm64/kernel/asm-offsets.c | 1 + > arch/arm64/kvm/hyp.S | 462 +++++++++++++++++++++++++++++++++++++++- > 2 files changed, 457 insertions(+), 6 deletions(-) > > diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c > index 646f888..ae73a83 100644 > --- a/arch/arm64/kernel/asm-offsets.c > +++ b/arch/arm64/kernel/asm-offsets.c > @@ -120,6 +120,7 @@ int main(void) > DEFINE(VCPU_ESR_EL2, offsetof(struct kvm_vcpu, arch.fault.esr_el2)); > DEFINE(VCPU_FAR_EL2, offsetof(struct kvm_vcpu, arch.fault.far_el2)); > DEFINE(VCPU_HPFAR_EL2, offsetof(struct kvm_vcpu, arch.fault.hpfar_el2)); > + DEFINE(VCPU_DEBUG_FLAGS, offsetof(struct kvm_vcpu, arch.debug_flags)); > DEFINE(VCPU_HCR_EL2, offsetof(struct kvm_vcpu, arch.hcr_el2)); > DEFINE(VCPU_IRQ_LINES, offsetof(struct kvm_vcpu, arch.irq_lines)); > DEFINE(VCPU_HOST_CONTEXT, offsetof(struct kvm_vcpu, arch.host_cpu_context)); > diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S > index b0d1512..727087c 100644 > --- a/arch/arm64/kvm/hyp.S > +++ b/arch/arm64/kvm/hyp.S > @@ -21,6 +21,7 @@ > #include <asm/assembler.h> > #include <asm/memory.h> > #include <asm/asm-offsets.h> > +#include <asm/debug-monitors.h> > #include <asm/fpsimdmacros.h> > #include <asm/kvm.h> > #include <asm/kvm_asm.h> > @@ -215,6 +216,7 @@ __kvm_hyp_code_start: > mrs x22, amair_el1 > mrs x23, cntkctl_el1 > mrs x24, par_el1 > + mrs x25, mdscr_el1 > > stp x4, x5, [x3] > stp x6, x7, [x3, #16] > @@ -226,7 +228,202 @@ __kvm_hyp_code_start: > stp x18, x19, [x3, #112] > stp x20, x21, [x3, #128] > stp x22, x23, [x3, #144] > - str x24, [x3, #160] > + stp x24, x25, [x3, #160] > +.endm > + > +.macro save_debug > + // x2: base address for cpu context > + // x3: tmp register > + > + mrs x26, id_aa64dfr0_el1 > + ubfx x24, x26, #12, #4 // Extract BRPs > + ubfx x25, x26, #20, #4 // Extract WRPs > + mov w26, #15 > + sub w24, w26, w24 // How many BPs to skip > + sub w25, w26, w25 // How many WPs to skip > + > + add x3, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1) > + > + adr x26, 1f > + add x26, x26, x24, lsl #2 > + br x26 > +1: > + mrs x20, dbgbcr15_el1 > + mrs x19, dbgbcr14_el1 > + mrs x18, dbgbcr13_el1 > + mrs x17, dbgbcr12_el1 > + mrs x16, dbgbcr11_el1 > + mrs x15, dbgbcr10_el1 > + mrs x14, dbgbcr9_el1 > + mrs x13, dbgbcr8_el1 > + mrs x12, dbgbcr7_el1 > + mrs x11, dbgbcr6_el1 > + mrs x10, dbgbcr5_el1 > + mrs x9, dbgbcr4_el1 > + mrs x8, dbgbcr3_el1 > + mrs x7, dbgbcr2_el1 > + mrs x6, dbgbcr1_el1 > + mrs x5, dbgbcr0_el1 > + > + adr x26, 1f > + add x26, x26, x24, lsl #2 > + br x26 > + > +1: > + str x20, [x3, #(15 * 8)] > + str x19, [x3, #(14 * 8)] > + str x18, [x3, #(13 * 8)] > + str x17, [x3, #(12 * 8)] > + str x16, [x3, #(11 * 8)] > + str x15, [x3, #(10 * 8)] > + str x14, [x3, #(9 * 8)] > + str x13, [x3, #(8 * 8)] > + str x12, [x3, #(7 * 8)] > + str x11, [x3, #(6 * 8)] > + str x10, [x3, #(5 * 8)] > + str x9, [x3, #(4 * 8)] > + str x8, [x3, #(3 * 8)] > + str x7, [x3, #(2 * 8)] > + str x6, [x3, #(1 * 8)] > + str x5, [x3, #(0 * 8)] > + > + add x3, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1) > + > + adr x26, 1f > + add x26, x26, x24, lsl #2 > + br x26 > +1: > + mrs x20, dbgbvr15_el1 > + mrs x19, dbgbvr14_el1 > + mrs x18, dbgbvr13_el1 > + mrs x17, dbgbvr12_el1 > + mrs x16, dbgbvr11_el1 > + mrs x15, dbgbvr10_el1 > + mrs x14, dbgbvr9_el1 > + mrs x13, dbgbvr8_el1 > + mrs x12, dbgbvr7_el1 > + mrs x11, dbgbvr6_el1 > + mrs x10, dbgbvr5_el1 > + mrs x9, dbgbvr4_el1 > + mrs x8, dbgbvr3_el1 > + mrs x7, dbgbvr2_el1 > + mrs x6, dbgbvr1_el1 > + mrs x5, dbgbvr0_el1 > + > + adr x26, 1f > + add x26, x26, x24, lsl #2 > + br x26 > + > +1: > + str x20, [x3, #(15 * 8)] > + str x19, [x3, #(14 * 8)] > + str x18, [x3, #(13 * 8)] > + str x17, [x3, #(12 * 8)] > + str x16, [x3, #(11 * 8)] > + str x15, [x3, #(10 * 8)] > + str x14, [x3, #(9 * 8)] > + str x13, [x3, #(8 * 8)] > + str x12, [x3, #(7 * 8)] > + str x11, [x3, #(6 * 8)] > + str x10, [x3, #(5 * 8)] > + str x9, [x3, #(4 * 8)] > + str x8, [x3, #(3 * 8)] > + str x7, [x3, #(2 * 8)] > + str x6, [x3, #(1 * 8)] > + str x5, [x3, #(0 * 8)] > + > + add x3, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1) > + > + adr x26, 1f > + add x26, x26, x25, lsl #2 > + br x26 > +1: > + mrs x20, dbgwcr15_el1 > + mrs x19, dbgwcr14_el1 > + mrs x18, dbgwcr13_el1 > + mrs x17, dbgwcr12_el1 > + mrs x16, dbgwcr11_el1 > + mrs x15, dbgwcr10_el1 > + mrs x14, dbgwcr9_el1 > + mrs x13, dbgwcr8_el1 > + mrs x12, dbgwcr7_el1 > + mrs x11, dbgwcr6_el1 > + mrs x10, dbgwcr5_el1 > + mrs x9, dbgwcr4_el1 > + mrs x8, dbgwcr3_el1 > + mrs x7, dbgwcr2_el1 > + mrs x6, dbgwcr1_el1 > + mrs x5, dbgwcr0_el1 > + > + adr x26, 1f > + add x26, x26, x25, lsl #2 > + br x26 > + > +1: > + str x20, [x3, #(15 * 8)] > + str x19, [x3, #(14 * 8)] > + str x18, [x3, #(13 * 8)] > + str x17, [x3, #(12 * 8)] > + str x16, [x3, #(11 * 8)] > + str x15, [x3, #(10 * 8)] > + str x14, [x3, #(9 * 8)] > + str x13, [x3, #(8 * 8)] > + str x12, [x3, #(7 * 8)] > + str x11, [x3, #(6 * 8)] > + str x10, [x3, #(5 * 8)] > + str x9, [x3, #(4 * 8)] > + str x8, [x3, #(3 * 8)] > + str x7, [x3, #(2 * 8)] > + str x6, [x3, #(1 * 8)] > + str x5, [x3, #(0 * 8)] > + > + add x3, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1) > + > + adr x26, 1f > + add x26, x26, x25, lsl #2 > + br x26 > +1: > + mrs x20, dbgwvr15_el1 > + mrs x19, dbgwvr14_el1 > + mrs x18, dbgwvr13_el1 > + mrs x17, dbgwvr12_el1 > + mrs x16, dbgwvr11_el1 > + mrs x15, dbgwvr10_el1 > + mrs x14, dbgwvr9_el1 > + mrs x13, dbgwvr8_el1 > + mrs x12, dbgwvr7_el1 > + mrs x11, dbgwvr6_el1 > + mrs x10, dbgwvr5_el1 > + mrs x9, dbgwvr4_el1 > + mrs x8, dbgwvr3_el1 > + mrs x7, dbgwvr2_el1 > + mrs x6, dbgwvr1_el1 > + mrs x5, dbgwvr0_el1 > + > + adr x26, 1f > + add x26, x26, x25, lsl #2 > + br x26 > + > +1: > + str x20, [x3, #(15 * 8)] > + str x19, [x3, #(14 * 8)] > + str x18, [x3, #(13 * 8)] > + str x17, [x3, #(12 * 8)] > + str x16, [x3, #(11 * 8)] > + str x15, [x3, #(10 * 8)] > + str x14, [x3, #(9 * 8)] > + str x13, [x3, #(8 * 8)] > + str x12, [x3, #(7 * 8)] > + str x11, [x3, #(6 * 8)] > + str x10, [x3, #(5 * 8)] > + str x9, [x3, #(4 * 8)] > + str x8, [x3, #(3 * 8)] > + str x7, [x3, #(2 * 8)] > + str x6, [x3, #(1 * 8)] > + str x5, [x3, #(0 * 8)] > + > + mrs x21, mdccint_el1 > + str x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)] > .endm > > .macro restore_sysregs > @@ -245,7 +442,7 @@ __kvm_hyp_code_start: > ldp x18, x19, [x3, #112] > ldp x20, x21, [x3, #128] > ldp x22, x23, [x3, #144] > - ldr x24, [x3, #160] > + ldp x24, x25, [x3, #160] > > msr vmpidr_el2, x4 > msr csselr_el1, x5 > @@ -268,6 +465,198 @@ __kvm_hyp_code_start: > msr amair_el1, x22 > msr cntkctl_el1, x23 > msr par_el1, x24 > + msr mdscr_el1, x25 > +.endm > + > +.macro restore_debug > + // x2: base address for cpu context > + // x3: tmp register > + > + mrs x26, id_aa64dfr0_el1 > + ubfx x24, x26, #12, #4 // Extract BRPs > + ubfx x25, x26, #20, #4 // Extract WRPs > + mov w26, #15 > + sub w24, w26, w24 // How many BPs to skip > + sub w25, w26, w25 // How many WPs to skip > + > + add x3, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1) > + > + adr x26, 1f > + add x26, x26, x24, lsl #2 > + br x26 > +1: > + ldr x20, [x3, #(15 * 8)] > + ldr x19, [x3, #(14 * 8)] > + ldr x18, [x3, #(13 * 8)] > + ldr x17, [x3, #(12 * 8)] > + ldr x16, [x3, #(11 * 8)] > + ldr x15, [x3, #(10 * 8)] > + ldr x14, [x3, #(9 * 8)] > + ldr x13, [x3, #(8 * 8)] > + ldr x12, [x3, #(7 * 8)] > + ldr x11, [x3, #(6 * 8)] > + ldr x10, [x3, #(5 * 8)] > + ldr x9, [x3, #(4 * 8)] > + ldr x8, [x3, #(3 * 8)] > + ldr x7, [x3, #(2 * 8)] > + ldr x6, [x3, #(1 * 8)] > + ldr x5, [x3, #(0 * 8)] > + > + adr x26, 1f > + add x26, x26, x24, lsl #2 > + br x26 > +1: > + msr dbgbcr15_el1, x20 > + msr dbgbcr14_el1, x19 > + msr dbgbcr13_el1, x18 > + msr dbgbcr12_el1, x17 > + msr dbgbcr11_el1, x16 > + msr dbgbcr10_el1, x15 > + msr dbgbcr9_el1, x14 > + msr dbgbcr8_el1, x13 > + msr dbgbcr7_el1, x12 > + msr dbgbcr6_el1, x11 > + msr dbgbcr5_el1, x10 > + msr dbgbcr4_el1, x9 > + msr dbgbcr3_el1, x8 > + msr dbgbcr2_el1, x7 > + msr dbgbcr1_el1, x6 > + msr dbgbcr0_el1, x5 > + > + add x3, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1) > + > + adr x26, 1f > + add x26, x26, x24, lsl #2 > + br x26 > +1: > + ldr x20, [x3, #(15 * 8)] > + ldr x19, [x3, #(14 * 8)] > + ldr x18, [x3, #(13 * 8)] > + ldr x17, [x3, #(12 * 8)] > + ldr x16, [x3, #(11 * 8)] > + ldr x15, [x3, #(10 * 8)] > + ldr x14, [x3, #(9 * 8)] > + ldr x13, [x3, #(8 * 8)] > + ldr x12, [x3, #(7 * 8)] > + ldr x11, [x3, #(6 * 8)] > + ldr x10, [x3, #(5 * 8)] > + ldr x9, [x3, #(4 * 8)] > + ldr x8, [x3, #(3 * 8)] > + ldr x7, [x3, #(2 * 8)] > + ldr x6, [x3, #(1 * 8)] > + ldr x5, [x3, #(0 * 8)] > + > + adr x26, 1f > + add x26, x26, x24, lsl #2 > + br x26 > +1: > + msr dbgbvr15_el1, x20 > + msr dbgbvr14_el1, x19 > + msr dbgbvr13_el1, x18 > + msr dbgbvr12_el1, x17 > + msr dbgbvr11_el1, x16 > + msr dbgbvr10_el1, x15 > + msr dbgbvr9_el1, x14 > + msr dbgbvr8_el1, x13 > + msr dbgbvr7_el1, x12 > + msr dbgbvr6_el1, x11 > + msr dbgbvr5_el1, x10 > + msr dbgbvr4_el1, x9 > + msr dbgbvr3_el1, x8 > + msr dbgbvr2_el1, x7 > + msr dbgbvr1_el1, x6 > + msr dbgbvr0_el1, x5 > + > + add x3, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1) > + > + adr x26, 1f > + add x26, x26, x25, lsl #2 > + br x26 > +1: > + ldr x20, [x3, #(15 * 8)] > + ldr x19, [x3, #(14 * 8)] > + ldr x18, [x3, #(13 * 8)] > + ldr x17, [x3, #(12 * 8)] > + ldr x16, [x3, #(11 * 8)] > + ldr x15, [x3, #(10 * 8)] > + ldr x14, [x3, #(9 * 8)] > + ldr x13, [x3, #(8 * 8)] > + ldr x12, [x3, #(7 * 8)] > + ldr x11, [x3, #(6 * 8)] > + ldr x10, [x3, #(5 * 8)] > + ldr x9, [x3, #(4 * 8)] > + ldr x8, [x3, #(3 * 8)] > + ldr x7, [x3, #(2 * 8)] > + ldr x6, [x3, #(1 * 8)] > + ldr x5, [x3, #(0 * 8)] > + > + adr x26, 1f > + add x26, x26, x25, lsl #2 > + br x26 > +1: > + msr dbgwcr15_el1, x20 > + msr dbgwcr14_el1, x19 > + msr dbgwcr13_el1, x18 > + msr dbgwcr12_el1, x17 > + msr dbgwcr11_el1, x16 > + msr dbgwcr10_el1, x15 > + msr dbgwcr9_el1, x14 > + msr dbgwcr8_el1, x13 > + msr dbgwcr7_el1, x12 > + msr dbgwcr6_el1, x11 > + msr dbgwcr5_el1, x10 > + msr dbgwcr4_el1, x9 > + msr dbgwcr3_el1, x8 > + msr dbgwcr2_el1, x7 > + msr dbgwcr1_el1, x6 > + msr dbgwcr0_el1, x5 > + > + add x3, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1) > + > + adr x26, 1f > + add x26, x26, x25, lsl #2 > + br x26 > +1: > + ldr x20, [x3, #(15 * 8)] > + ldr x19, [x3, #(14 * 8)] > + ldr x18, [x3, #(13 * 8)] > + ldr x17, [x3, #(12 * 8)] > + ldr x16, [x3, #(11 * 8)] > + ldr x15, [x3, #(10 * 8)] > + ldr x14, [x3, #(9 * 8)] > + ldr x13, [x3, #(8 * 8)] > + ldr x12, [x3, #(7 * 8)] > + ldr x11, [x3, #(6 * 8)] > + ldr x10, [x3, #(5 * 8)] > + ldr x9, [x3, #(4 * 8)] > + ldr x8, [x3, #(3 * 8)] > + ldr x7, [x3, #(2 * 8)] > + ldr x6, [x3, #(1 * 8)] > + ldr x5, [x3, #(0 * 8)] > + > + adr x26, 1f > + add x26, x26, x25, lsl #2 > + br x26 > +1: > + msr dbgwvr15_el1, x20 > + msr dbgwvr14_el1, x19 > + msr dbgwvr13_el1, x18 > + msr dbgwvr12_el1, x17 > + msr dbgwvr11_el1, x16 > + msr dbgwvr10_el1, x15 > + msr dbgwvr9_el1, x14 > + msr dbgwvr8_el1, x13 > + msr dbgwvr7_el1, x12 > + msr dbgwvr6_el1, x11 > + msr dbgwvr5_el1, x10 > + msr dbgwvr4_el1, x9 > + msr dbgwvr3_el1, x8 > + msr dbgwvr2_el1, x7 > + msr dbgwvr1_el1, x6 > + msr dbgwvr0_el1, x5 > + > + ldr x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)] > + msr mdccint_el1, x21 > .endm > > .macro skip_32bit_state tmp, target > @@ -282,6 +671,35 @@ __kvm_hyp_code_start: > tbz \tmp, #12, \target > .endm > > +.macro skip_debug_state tmp, target > + ldr \tmp, [x0, #VCPU_DEBUG_FLAGS] > + tbz \tmp, #KVM_ARM64_DEBUG_DIRTY_SHIFT, \target > +.endm > + > +.macro compute_debug_state target > + // Compute debug state: If any of KDE, MDE or KVM_ARM64_DEBUG_DIRTY > + // is set, we do a full save/restore cycle and disable trapping. > + add x25, x0, #VCPU_CONTEXT > + > + // Check the state of MDSCR_EL1 > + ldr x25, [x25, #CPU_SYSREG_OFFSET(MDSCR_EL1)] > + and x26, x25, #DBG_MDSCR_KDE > + and x25, x25, #DBG_MDSCR_MDE > + adds xzr, x25, x26 > + b.eq 9998f // Nothing to see there > + > + // If any interesting bits was set, we must set the flag > + mov x26, #KVM_ARM64_DEBUG_DIRTY > + str x26, [x0, #VCPU_DEBUG_FLAGS] > + b 9999f // Don't skip restore > + > +9998: > + // Otherwise load the flags from memory in case we recently > + // trapped > + skip_debug_state x25, \target > +9999: > +.endm > + > .macro save_guest_32bit_state > skip_32bit_state x3, 1f > > @@ -297,10 +715,13 @@ __kvm_hyp_code_start: > mrs x4, dacr32_el2 > mrs x5, ifsr32_el2 > mrs x6, fpexc32_el2 > - mrs x7, dbgvcr32_el2 > stp x4, x5, [x3] > - stp x6, x7, [x3, #16] > + str x6, [x3, #16] > > + skip_debug_state x8, 2f > + mrs x7, dbgvcr32_el2 > + str x7, [x3, #24] > +2: > skip_tee_state x8, 1f > > add x3, x2, #CPU_SYSREG_OFFSET(TEECR32_EL1) > @@ -323,12 +744,15 @@ __kvm_hyp_code_start: > > add x3, x2, #CPU_SYSREG_OFFSET(DACR32_EL2) > ldp x4, x5, [x3] > - ldp x6, x7, [x3, #16] > + ldr x6, [x3, #16] > msr dacr32_el2, x4 > msr ifsr32_el2, x5 > msr fpexc32_el2, x6 > - msr dbgvcr32_el2, x7 > > + skip_debug_state x8, 2f > + ldr x7, [x3, #24] > + msr dbgvcr32_el2, x7 > +2: > skip_tee_state x8, 1f > > add x3, x2, #CPU_SYSREG_OFFSET(TEECR32_EL1) > @@ -537,6 +961,14 @@ __restore_sysregs: > restore_sysregs > ret > > +__save_debug: > + save_debug > + ret > + > +__restore_debug: > + restore_debug > + ret > + > __save_fpsimd: > save_fpsimd > ret > @@ -568,6 +1000,9 @@ ENTRY(__kvm_vcpu_run) > bl __save_fpsimd > bl __save_sysregs > > + compute_debug_state 1f > + bl __save_debug > +1: > activate_traps > activate_vm > > @@ -579,6 +1014,10 @@ ENTRY(__kvm_vcpu_run) > > bl __restore_sysregs > bl __restore_fpsimd > + > + skip_debug_state x3, 1f > + bl __restore_debug > +1: > restore_guest_32bit_state > restore_guest_regs > > @@ -595,6 +1034,10 @@ __kvm_vcpu_return: > save_guest_regs > bl __save_fpsimd > bl __save_sysregs > + > + skip_debug_state x3, 1f > + bl __save_debug > +1: > save_guest_32bit_state > > save_timer_state > @@ -609,6 +1052,13 @@ __kvm_vcpu_return: > > bl __restore_sysregs > bl __restore_fpsimd > + > + skip_debug_state x3, 1f > + // Clear the dirty flag for the next run, as all the state has > + // already been saved. > + str xzr, [x0, #VCPU_DEBUG_FLAGS] > + bl __restore_debug > +1: > restore_host_regs > > mov x0, x1 > -- > 1.8.3.4 > let's just try to remember the fact that we overwrite the entire bitmask here if we add more bits to that value some time: Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
