| Message ID | 1436372356-30410-8-git-send-email-marc.zyngier@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 08/07/2015 18:19, Marc Zyngier wrote: > +/* Hack to allow stringification of macros... */ > +#define __S__(a,args...) __stringify(a, ##args) > +#define _S_(a,args...) __S__(a, args) > + > +.macro ifnvhe nonvhe vhe > + alternative_insn "\nonvhe", "\vhe", ARM64_HAS_VIRT_HOST_EXTN > +.endm Why not use this in patch 6 too? Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/07/15 18:14, Paolo Bonzini wrote: > > > On 08/07/2015 18:19, Marc Zyngier wrote: >> +/* Hack to allow stringification of macros... */ >> +#define __S__(a,args...) __stringify(a, ##args) >> +#define _S_(a,args...) __S__(a, args) >> + >> +.macro ifnvhe nonvhe vhe >> + alternative_insn "\nonvhe", "\vhe", ARM64_HAS_VIRT_HOST_EXTN >> +.endm > > Why not use this in patch 6 too? I tried, and ended up in #include hell. vhe-macros.h is local to arch/arm64/kvm, and including it from asm/kvm_mmu.h breaks (we include it from arch/arm/kvm/ and virt/kvm/arm/). Alternatively, I could move it to arch/arm64/include/asm (renamed to kvm_vhe_macros.h?), which would solve this issue. I just gave it a go, and that seems sensible enough. Thanks for the suggestion! M.
On 08/07/2015 19:54, Marc Zyngier wrote: > Alternatively, I could move it to arch/arm64/include/asm (renamed to > kvm_vhe_macros.h?), which would solve this issue. I just gave it a go, > and that seems sensible enough. Yes, that would do. Alternatively: * create kvm_hyp_macros.h and put more stuff in there from kvm_mmu.h * just put it in kvm_host.h Whatever looks better to you. Paolo > Thanks for the suggestion! -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Jul 08, 2015 at 05:19:10PM +0100, Marc Zyngier wrote: > --- /dev/null > +++ b/arch/arm64/kvm/vhe-macros.h > @@ -0,0 +1,36 @@ > +/* > + * 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/>. > + */ > + > +#ifndef __ARM64_VHE_MACROS_H__ > +#define __ARM64_VHE_MACROS_H__ > + > +#include <asm/alternative.h> > +#include <asm/cpufeature.h> > + > +#ifdef __ASSEMBLY__ > + > +/* Hack to allow stringification of macros... */ > +#define __S__(a,args...) __stringify(a, ##args) > +#define _S_(a,args...) __S__(a, args) > + > +.macro ifnvhe nonvhe vhe > + alternative_insn "\nonvhe", "\vhe", ARM64_HAS_VIRT_HOST_EXTN > +.endm I always found the alternative_insn tricks hard to read but with Daniel's patch queued in -next it gets slightly better. If you are not targeting 4.3, could you do something like (untested): .macro vhe_if_not alternative_if_not ARM64_HAS_VIRT_HOST_EXTN .endm .macro vhe_else alternative_else CONFIG_ARM64_VHE .endm .macro vhe_endif alternative_endif CONFIG_ARM64_VHE .endm The kvm_call_hyp, for example, would become: ENTRY(kvm_call_hyp) vhe_if_not hvc #0 ret vhe_else nop push lr, xzr vhe_endif Or you can even ignore defining new vhe_* macros altogether and just use "alternative_if_not ARM64_HAS_VIRT_HOST_EXTN" directly (more to type) but you may be able to avoid a vhe-macros.h file.
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S index 17a8fb1..a65e053 100644 --- a/arch/arm64/kvm/hyp.S +++ b/arch/arm64/kvm/hyp.S @@ -30,6 +30,8 @@ #include <asm/kvm_mmu.h> #include <asm/memory.h> +#include "vhe-macros.h" + #define CPU_GP_REG_OFFSET(x) (CPU_GP_REGS + x) #define CPU_XREG_OFFSET(x) CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x) #define CPU_SPSR_OFFSET(x) CPU_GP_REG_OFFSET(CPU_SPSR + 8*x) @@ -39,6 +41,19 @@ .pushsection .hyp.text, "ax" .align PAGE_SHIFT +.macro do_el2_call + /* + * Shuffle the parameters before calling the function + * pointed to in x0. Assumes parameters in x[1,2,3], + * clobbers lr. + */ + mov lr, x0 + mov x0, x1 + mov x1, x2 + mov x2, x3 + blr lr +.endm + .macro save_common_regs // x2: base address for cpu context // x3: tmp register @@ -1124,7 +1139,23 @@ __hyp_panic_str: * arch/arm64/kernel/hyp_stub.S. */ ENTRY(kvm_call_hyp) - hvc #0 + /* + * NOP out the hvc/ret sequence on VHE, and fall through. + */ +ifnvhe hvc #0, nop +ifnvhe ret, "push lr, xzr" + + do_el2_call + + /* + * We used to rely on having an exception return to get + * an implicit isb. In the E2H case, we don't have it anymore. + * rather than changing all the leaf functions, just do it here + * before returning to the rest of the kernel. + */ + isb + + pop lr, xzr ret ENDPROC(kvm_call_hyp) @@ -1156,7 +1187,9 @@ el1_sync: // Guest trapped into EL2 mrs x1, esr_el2 lsr x2, x1, #ESR_ELx_EC_SHIFT - cmp x2, #ESR_ELx_EC_HVC64 + // Ugly shortcut for VHE. We can do this early because the + // host cannot do an HVC. +ifnvhe _S_(cmp x2, #ESR_ELx_EC_HVC64), "b el1_trap" b.ne el1_trap mrs x3, vttbr_el2 // If vttbr is valid, the 64bit guest @@ -1177,11 +1210,7 @@ el1_sync: // Guest trapped into EL2 * Compute the function address in EL2, and shuffle the parameters. */ kern_hyp_va x0 - mov lr, x0 - mov x0, x1 - mov x1, x2 - mov x2, x3 - blr lr + do_el2_call pop lr, xzr 2: eret diff --git a/arch/arm64/kvm/vhe-macros.h b/arch/arm64/kvm/vhe-macros.h new file mode 100644 index 0000000..da7f9da --- /dev/null +++ b/arch/arm64/kvm/vhe-macros.h @@ -0,0 +1,36 @@ +/* + * 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/>. + */ + +#ifndef __ARM64_VHE_MACROS_H__ +#define __ARM64_VHE_MACROS_H__ + +#include <asm/alternative.h> +#include <asm/cpufeature.h> + +#ifdef __ASSEMBLY__ + +/* Hack to allow stringification of macros... */ +#define __S__(a,args...) __stringify(a, ##args) +#define _S_(a,args...) __S__(a, args) + +.macro ifnvhe nonvhe vhe + alternative_insn "\nonvhe", "\vhe", ARM64_HAS_VIRT_HOST_EXTN +.endm + +#endif + +#endif /*__ARM64_VHE_MACROS_H__ */
With VHE, the host never issues an HVC instruction to get into the KVM code, as we can simply branch there. Use runtime code patching to simplify things a bit. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- arch/arm64/kvm/hyp.S | 43 ++++++++++++++++++++++++++++++++++++------- arch/arm64/kvm/vhe-macros.h | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 72 insertions(+), 7 deletions(-) create mode 100644 arch/arm64/kvm/vhe-macros.h