From: David Daney <ddaney.cavm@gmail.com>
To: linux-mips@linux-mips.org, ralf@linux-mips.org,
kvm@vger.kernel.org, Sanjay Lal <sanjayl@kymasys.com>
Cc: linux-kernel@vger.kernel.org, David Daney <david.daney@cavium.com>
Subject: [PATCH 15/31] mips/kvm: Exception handling to leave and reenter guest mode.
Date: Fri, 7 Jun 2013 16:03:19 -0700 [thread overview]
Message-ID: <1370646215-6543-16-git-send-email-ddaney.cavm@gmail.com> (raw)
In-Reply-To: <1370646215-6543-1-git-send-email-ddaney.cavm@gmail.com>
From: David Daney <david.daney@cavium.com>
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 <david.daney@cavium.com>
---
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 <asm/asmmacro.h>
#include <asm/mipsregs.h>
#include <asm/asm-offsets.h>
+#include <asm/thread_info.h>
/*
* 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
next prev parent reply other threads:[~2013-06-07 23:09 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-07 23:03 [PATCH 00/31] KVM/MIPS: Implement hardware virtualization via the MIPS-VZ extensions David Daney
2013-06-07 23:03 ` [PATCH 01/31] MIPS: Move allocate_kscratch to cpu-probe.c and make it public David Daney
2013-06-14 11:41 ` Ralf Baechle
2013-06-14 13:11 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 02/31] MIPS: Save and restore K0/K1 when CONFIG_KVM_MIPSVZ David Daney
2013-06-07 23:03 ` [PATCH 03/31] mips/kvm: Fix 32-bitisms in kvm_locore.S David Daney
2013-06-14 13:09 ` Ralf Baechle
2013-06-14 13:21 ` Sergei Shtylyov
2013-06-07 23:03 ` [PATCH 04/31] mips/kvm: Add casts to avoid pointer width mismatch build failures David Daney
2013-06-14 13:14 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 05/31] mips/kvm: Use generic cache flushing functions David Daney
2013-06-14 13:17 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 06/31] mips/kvm: Rename kvm_vcpu_arch.pc to kvm_vcpu_arch.epc David Daney
2013-06-14 13:18 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 07/31] mips/kvm: Rename VCPU_registername to KVM_VCPU_ARCH_registername David Daney
2013-06-14 13:18 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 08/31] mips/kvm: Fix code formatting in arch/mips/kvm/kvm_locore.S David Daney
2013-06-14 13:21 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 09/31] mips/kvm: Factor trap-and-emulate support into a pluggable implementation David Daney
2013-06-14 13:22 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 10/31] mips/kvm: Implement ioctls to get and set FPU registers David Daney
2013-06-14 16:11 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 11/31] MIPS: Rearrange branch.c so it can be used by kvm code David Daney
2013-06-14 22:03 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 12/31] MIPS: Add instruction format information for WAIT, MTC0, MFC0, et al David Daney
2013-06-14 22:07 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 13/31] mips/kvm: Add accessors for MIPS VZ registers David Daney
2013-06-14 22:10 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 14/31] mips/kvm: Add thread_info flag to indicate operation in MIPS VZ Guest Mode David Daney
2013-06-14 22:10 ` Ralf Baechle
2013-06-07 23:03 ` David Daney [this message]
2013-06-15 10:00 ` [PATCH 15/31] mips/kvm: Exception handling to leave and reenter guest mode Ralf Baechle
2013-10-11 12:51 ` James Hogan
2013-06-07 23:03 ` [PATCH 16/31] mips/kvm: Add exception handler for MIPSVZ Guest exceptions David Daney
2013-06-15 10:23 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 17/31] MIPS: Quit exposing Kconfig symbols in uapi headers David Daney
2013-06-14 11:12 ` Ralf Baechle
2013-06-15 17:13 ` Paolo Bonzini
2013-06-07 23:03 ` [PATCH 18/31] mips/kvm: Add pt_regs slots for BadInstr and BadInstrP David Daney
2013-06-15 10:25 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 19/31] mips/kvm: Add host definitions for MIPS VZ based host David Daney
2013-06-16 8:49 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 20/31] mips/kvm: Hook into TLB fault handlers David Daney
2013-06-07 23:34 ` Sergei Shtylyov
2013-06-08 0:15 ` David Daney
2013-06-16 8:51 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 21/31] mips/kvm: Allow set_except_vector() to be used from MIPSVZ code David Daney
2013-06-16 11:22 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 22/31] mips/kvm: Split get_new_mmu_context into two parts David Daney
2013-06-16 11:26 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 23/31] mips/kvm: Hook into CP unusable exception handler David Daney
2013-06-16 11:28 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 24/31] mips/kvm: Add thread_struct fields used by MIPSVZ hosts David Daney
2013-06-16 11:29 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 25/31] mips/kvm: Add some asm-offsets constants used by MIPSVZ David Daney
2013-06-16 11:31 ` Ralf Baechle
2013-08-06 17:23 ` David Daney
2013-06-07 23:03 ` [PATCH 26/31] mips/kvm: Split up Kconfig and Makefile definitions in preperation for MIPSVZ David Daney
2013-06-16 11:33 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 27/31] mips/kvm: Gate the use of kvm_local_flush_tlb_all() by KVM_MIPSTE David Daney
2013-06-16 11:42 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 28/31] mips/kvm: Only use KVM_COALESCED_MMIO_PAGE_OFFSET with KVM_MIPSTE David Daney
2013-06-16 12:03 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 29/31] mips/kvm: Add MIPSVZ support David Daney
2013-06-16 11:47 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 30/31] mips/kvm: Enable MIPSVZ in Kconfig/Makefile David Daney
2013-06-16 11:44 ` Ralf Baechle
2013-06-07 23:03 ` [PATCH 31/31] mips/kvm: Allow for upto 8 KVM vcpus per vm David Daney
2013-06-16 11:37 ` Ralf Baechle
2013-06-07 23:15 ` [PATCH 00/31] KVM/MIPS: Implement hardware virtualization via the MIPS-VZ extensions David Daney
2013-06-09 7:31 ` Gleb Natapov
2013-06-09 23:23 ` David Daney
2013-06-09 23:40 ` Maciej W. Rozycki
2013-06-10 11:16 ` Ralf Baechle
2013-06-10 6:18 ` Gleb Natapov
2013-06-10 16:37 ` Sanjay Lal
2013-06-16 11:59 ` Ralf Baechle
2013-06-10 16:43 ` Sanjay Lal
2013-06-10 17:14 ` David Daney
2013-06-14 11:12 ` Ralf Baechle
2013-06-19 9:06 ` Ralf Baechle
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