On Tue, Dec 01, 2015 at 03:47:37PM +0100, Christoffer Dall wrote: > On Tue, Dec 01, 2015 at 01:06:31PM +0000, Marc Zyngier wrote: > > On 01/12/15 12:56, Christoffer Dall wrote: > > > On Fri, Nov 27, 2015 at 06:50:02PM +0000, Marc Zyngier wrote: > > >> Implement the debug save restore as a direct translation of > > >> the assembly code version. > > >> > > >> Signed-off-by: Marc Zyngier <marc.zyng...@arm.com> > > >> --- > > >> arch/arm64/kvm/hyp/Makefile | 1 + > > >> arch/arm64/kvm/hyp/debug-sr.c | 130 > > >> ++++++++++++++++++++++++++++++++++++++++++ > > >> arch/arm64/kvm/hyp/hyp.h | 9 +++ > > >> 3 files changed, 140 insertions(+) > > >> create mode 100644 arch/arm64/kvm/hyp/debug-sr.c > > >> > > >> diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile > > >> index ec94200..ec14cac 100644 > > >> --- 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 > > >> index 0000000..a0b2b99 > > >> --- /dev/null > > >> +++ b/arch/arm64/kvm/hyp/debug-sr.c > > >> @@ -0,0 +1,130 @@ > > >> +/* > > >> + * Copyright (C) 2015 - ARM Ltd > > >> + * Author: Marc Zyngier <marc.zyng...@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) > > >> +{ > > >> + if (vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY) { > > >> + u64 aa64dfr0 = read_sysreg(id_aa64dfr0_el1); > > >> + int brps, wrps; > > >> + > > >> + 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) > > >> +{ > > >> + if (vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY) { > > >> + u64 aa64dfr0 = read_sysreg(id_aa64dfr0_el1); > > >> + int brps, wrps; > > >> + > > >> + 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 ((vcpu->arch.ctxt.sys_regs[MDSCR_EL1] & DBG_MDSCR_KDE) || > > >> + (vcpu->arch.ctxt.sys_regs[MDSCR_EL1] & DBG_MDSCR_KDE)) > > >> + 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)); > > > > > > doesn't the assmebly code jump across saving this state neither bits are > > > set where this always saves the state? > > > > It doesn't. The save/restore functions are guarded by tests on > > KVM_ARM64_DEBUG_DIRTY, just like we have skip_debug_state on all actions > > involving the save/restore in the assembly version. > > I think the confusing part is that the save function unconditionally > calls __debug_save_state where the restore function only calls it when > the dirty flag is set. Plus I suck at reading assembly apparently. > > > > > > in any case, I feel some context is lost when this is moved away from > > > assembly and understanding this patch would be easier if the semantics > > > of these two _cond functions were documented. > > > > I can migrate the existing comments if you think that helps. > > > It just wasn't not quite clear to me exactly when > __debug_cond_save_host_state is called for example - is this going to be > called unconditionally on every entry - that's how I understand it now > anyway. > Assuming I got that right:
Reviewed-by: Christoffer Dall <christoffer.d...@linaro.org> -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
