From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161052Ab3FGXJp (ORCPT ); Fri, 7 Jun 2013 19:09:45 -0400 Received: from mail-ie0-f171.google.com ([209.85.223.171]:49233 "EHLO mail-ie0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932091Ab3FGXDv (ORCPT ); Fri, 7 Jun 2013 19:03:51 -0400 From: David Daney To: linux-mips@linux-mips.org, ralf@linux-mips.org, kvm@vger.kernel.org, Sanjay Lal Cc: linux-kernel@vger.kernel.org, David Daney Subject: [PATCH 15/31] mips/kvm: Exception handling to leave and reenter guest mode. Date: Fri, 7 Jun 2013 16:03:19 -0700 Message-Id: <1370646215-6543-16-git-send-email-ddaney.cavm@gmail.com> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1370646215-6543-1-git-send-email-ddaney.cavm@gmail.com> References: <1370646215-6543-1-git-send-email-ddaney.cavm@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Daney Currently this is a little complex, here are the facts about how it works: o When running in Guest mode we set the high bit of CP0_XCONTEXT. If this bit is clear, we don't do anything special on an exception. o If we are in guest mode, upon an exception we: 1) load the stack pointer from the mips_kvm_rootsp array instead of kernelsp. 2) Clear GuestCtl[GM] and high bit of CP0_XCONTEXT. 3) Restore host ASID and PGD pointer. o Upon restarting from an exception we test the task TIF_GUESTMODE flag if it is clear, nothing special is done. o If Guest mode is active for the thread we: 1) Compare the stack pointer to mips_kvm_rootsp, if it doesn't match we are not reentering guest mode, so no more special processing is done. 2) If reentering guest mode: 2a) Set high bit of CP0_XCONTEXT and GuestCtl[GM]. 2b) Set Guest mode ASID and PGD pointer. This allows a single set of exception handlers to be used for both host and guest mode operation. Signed-off-by: David Daney --- arch/mips/include/asm/stackframe.h | 135 ++++++++++++++++++++++++++++++++++++- 1 file changed, 132 insertions(+), 3 deletions(-) diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h index 20627b2..bf2ec48 100644 --- a/arch/mips/include/asm/stackframe.h +++ b/arch/mips/include/asm/stackframe.h @@ -17,6 +17,7 @@ #include #include #include +#include /* * For SMTC kernel, global IE should be left set, and interrupts @@ -98,7 +99,9 @@ #define CPU_ID_REG CP0_CONTEXT #define CPU_ID_MFC0 MFC0 #endif - .macro get_saved_sp /* SMP variation */ +#define CPU_ID_MASK ((1 << 13) - 1) + + .macro get_saved_sp_for_save_some /* SMP variation */ CPU_ID_MFC0 k0, CPU_ID_REG #if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32) lui k1, %hi(kernelsp) @@ -110,15 +113,49 @@ dsll k1, 16 #endif LONG_SRL k0, PTEBASE_SHIFT +#ifdef CONFIG_KVM_MIPSVZ + andi k0, CPU_ID_MASK /* high bits indicate guest mode. */ +#endif LONG_ADDU k1, k0 LONG_L k1, %lo(kernelsp)(k1) .endm + .macro get_saved_sp + CPU_ID_MFC0 k0, CPU_ID_REG + get_saved_sp_for_save_some + .endm + + .macro get_mips_kvm_rootsp /* SMP variation */ +#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32) + lui k1, %hi(mips_kvm_rootsp) +#else + lui k1, %highest(mips_kvm_rootsp) + daddiu k1, %higher(mips_kvm_rootsp) + dsll k1, 16 + daddiu k1, %hi(mips_kvm_rootsp) + dsll k1, 16 +#endif + LONG_SRL k0, PTEBASE_SHIFT + andi k0, CPU_ID_MASK /* high bits indicate guest mode. */ + LONG_ADDU k1, k0 + LONG_L k1, %lo(mips_kvm_rootsp)(k1) + .endm + .macro set_saved_sp stackp temp temp2 CPU_ID_MFC0 \temp, CPU_ID_REG LONG_SRL \temp, PTEBASE_SHIFT +#ifdef CONFIG_KVM_MIPSVZ + andi k0, CPU_ID_MASK /* high bits indicate guest mode. */ +#endif LONG_S \stackp, kernelsp(\temp) .endm + + .macro set_mips_kvm_rootsp stackp temp + CPU_ID_MFC0 \temp, CPU_ID_REG + LONG_SRL \temp, PTEBASE_SHIFT + andi k0, CPU_ID_MASK /* high bits indicate guest mode. */ + LONG_S \stackp, mips_kvm_rootsp(\temp) + .endm #else .macro get_saved_sp /* Uniprocessor variation */ #ifdef CONFIG_CPU_JUMP_WORKAROUNDS @@ -152,9 +189,27 @@ LONG_L k1, %lo(kernelsp)(k1) .endm + .macro get_mips_kvm_rootsp /* Uniprocessor variation */ +#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32) + lui k1, %hi(mips_kvm_rootsp) +#else + lui k1, %highest(mips_kvm_rootsp) + daddiu k1, %higher(mips_kvm_rootsp) + dsll k1, k1, 16 + daddiu k1, %hi(mips_kvm_rootsp) + dsll k1, k1, 16 +#endif + LONG_L k1, %lo(mips_kvm_rootsp)(k1) + .endm + + .macro set_saved_sp stackp temp temp2 LONG_S \stackp, kernelsp .endm + + .macro set_mips_kvm_rootsp stackp temp + LONG_S \stackp, mips_kvm_rootsp + .endm #endif .macro SAVE_SOME @@ -164,11 +219,21 @@ mfc0 k0, CP0_STATUS sll k0, 3 /* extract cu0 bit */ .set noreorder +#ifdef CONFIG_KVM_MIPSVZ + bgez k0, 7f + CPU_ID_MFC0 k0, CPU_ID_REG + bgez k0, 8f + move k1, sp + get_mips_kvm_rootsp + b 8f + nop +#else bltz k0, 8f move k1, sp +#endif .set reorder /* Called from user mode, new stack. */ - get_saved_sp +7: get_saved_sp_for_save_some #ifndef CONFIG_CPU_DADDI_WORKAROUNDS 8: move k0, sp PTR_SUBU sp, k1, PT_SIZE @@ -227,6 +292,35 @@ LONG_S $31, PT_R31(sp) ori $28, sp, _THREAD_MASK xori $28, _THREAD_MASK +#ifdef CONFIG_KVM_MIPSVZ + CPU_ID_MFC0 k0, CPU_ID_REG + .set noreorder + bgez k0, 8f + /* Must clear GuestCtl0[GM] */ + dins k0, zero, 63, 1 + .set reorder + dmtc0 k0, CPU_ID_REG + mfc0 k0, CP0_GUESTCTL0 + ins k0, zero, MIPS_GUESTCTL0B_GM, 1 + mtc0 k0, CP0_GUESTCTL0 + LONG_L v0, TI_TASK($28) + lw v1, THREAD_MM_ASID(v0) + dmtc0 v1, CP0_ENTRYHI + LONG_L v1, TASK_MM(v0) + .set noreorder + jal tlbmiss_handler_setup_pgd_array + LONG_L a0, MM_PGD(v1) + .set reorder + /* + * With KVM_MIPSVZ, we must not clobber k0/k1 + * they were saved before they were used + */ +8: + MFC0 k0, CP0_KSCRATCH1 + MFC0 v1, CP0_KSCRATCH2 + LONG_S k0, PT_R26(sp) + LONG_S v1, PT_R27(sp) +#endif #ifdef CONFIG_CPU_CAVIUM_OCTEON .set mips64 pref 0, 0($28) /* Prefetch the current pointer */ @@ -439,10 +533,45 @@ .set mips0 #endif /* CONFIG_MIPS_MT_SMTC */ LONG_L v1, PT_EPC(sp) + LONG_L $25, PT_R25(sp) MTC0 v1, CP0_EPC +#ifdef CONFIG_KVM_MIPSVZ + /* + * Only if TIF_GUESTMODE && sp is the saved KVM sp, return to + * guest mode. + */ + LONG_L v0, TI_FLAGS($28) + li k1, _TIF_GUESTMODE + and v0, v0, k1 + beqz v0, 8f + CPU_ID_MFC0 k0, CPU_ID_REG + get_mips_kvm_rootsp + PTR_SUBU k1, k1, PT_SIZE + bne k1, sp, 8f + /* Set the high order bit of CPU_ID_REG to indicate guest mode. */ + dli v0, 1 + dmfc0 v1, CPU_ID_REG + dins v1, v0, 63, 1 + dmtc0 v1, CPU_ID_REG + /* Must set GuestCtl0[GM] */ + mfc0 v1, CP0_GUESTCTL0 + ins v1, v0, MIPS_GUESTCTL0B_GM, 1 + mtc0 v1, CP0_GUESTCTL0 + + LONG_L v0, TI_TASK($28) + lw v1, THREAD_GUEST_ASID(v0) + dmtc0 v1, CP0_ENTRYHI + LONG_L v1, THREAD_VCPU(v0) + LONG_L v1, KVM_VCPU_KVM(v1) + LONG_L v1, KVM_ARCH_IMPL(v1) + .set noreorder + jal tlbmiss_handler_setup_pgd_array + LONG_L a0, KVM_MIPS_VZ_PGD(v1) + .set reorder +8: +#endif LONG_L $31, PT_R31(sp) LONG_L $28, PT_R28(sp) - LONG_L $25, PT_R25(sp) #ifdef CONFIG_64BIT LONG_L $8, PT_R8(sp) LONG_L $9, PT_R9(sp) -- 1.7.11.7