KVM: PPC: Add generic segment switching code
This is the code that will later be used instead of book3s_64_slb.S. It
does the last step of guest entry and the first generic steps of guest
exiting, once we have determined the interrupt is a KVM interrupt.
It also reads the last used instruction from the guest virtual address
space if necessary, to speed up that path.
The new thing about this file is that it makes use of generic long load
and store functions and calls a macro to fill in the actual segment
switching code. That still needs to be done differently for book3s_32 and
book3s_64.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/kvm/book3s_segment.S b/arch/powerpc/kvm/book3s_segment.S
new file mode 100644
index 0000000..4c0d1d8
--- /dev/null
+++ b/arch/powerpc/kvm/book3s_segment.S
@@ -0,0 +1,257 @@
+/*
+ * 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, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * Copyright SUSE Linux Products GmbH 2010
+ *
+ * Authors: Alexander Graf <agraf@suse.de>
+ */
+
+/* Real mode helpers */
+
+#if defined(CONFIG_PPC_BOOK3S_64)
+
+#define GET_SHADOW_VCPU(reg) \
+ addi reg, r13, PACA_KVM_SVCPU
+
+#elif defined(CONFIG_PPC_BOOK3S_32)
+
+#define GET_SHADOW_VCPU(reg) \
+ tophys(reg, r2); \
+ lwz reg, (THREAD + THREAD_KVM_SVCPU)(reg); \
+ tophys(reg, reg)
+
+#endif
+
+/* Disable for nested KVM */
+#define USE_QUICK_LAST_INST
+
+
+/* Get helper functions for subarch specific functionality */
+
+#if defined(CONFIG_PPC_BOOK3S_64)
+#include "book3s_64_slb.S"
+#elif defined(CONFIG_PPC_BOOK3S_32)
+#include "book3s_32_sr.S"
+#endif
+
+/******************************************************************************
+ * *
+ * Entry code *
+ * *
+ *****************************************************************************/
+
+.global kvmppc_handler_trampoline_enter
+kvmppc_handler_trampoline_enter:
+
+ /* Required state:
+ *
+ * MSR = ~IR|DR
+ * R13 = PACA
+ * R1 = host R1
+ * R2 = host R2
+ * R10 = guest MSR
+ * all other volatile GPRS = free
+ * SVCPU[CR] = guest CR
+ * SVCPU[XER] = guest XER
+ * SVCPU[CTR] = guest CTR
+ * SVCPU[LR] = guest LR
+ */
+
+ /* r3 = shadow vcpu */
+ GET_SHADOW_VCPU(r3)
+
+ /* Move SRR0 and SRR1 into the respective regs */
+ PPC_LL r9, SVCPU_PC(r3)
+ mtsrr0 r9
+ mtsrr1 r10
+
+ /* Activate guest mode, so faults get handled by KVM */
+ li r11, KVM_GUEST_MODE_GUEST
+ stb r11, SVCPU_IN_GUEST(r3)
+
+ /* Switch to guest segment. This is subarch specific. */
+ LOAD_GUEST_SEGMENTS
+
+ /* Enter guest */
+
+ PPC_LL r4, (SVCPU_CTR)(r3)
+ PPC_LL r5, (SVCPU_LR)(r3)
+ lwz r6, (SVCPU_CR)(r3)
+ lwz r7, (SVCPU_XER)(r3)
+
+ mtctr r4
+ mtlr r5
+ mtcr r6
+ mtxer r7
+
+ PPC_LL r0, (SVCPU_R0)(r3)
+ PPC_LL r1, (SVCPU_R1)(r3)
+ PPC_LL r2, (SVCPU_R2)(r3)
+ PPC_LL r4, (SVCPU_R4)(r3)
+ PPC_LL r5, (SVCPU_R5)(r3)
+ PPC_LL r6, (SVCPU_R6)(r3)
+ PPC_LL r7, (SVCPU_R7)(r3)
+ PPC_LL r8, (SVCPU_R8)(r3)
+ PPC_LL r9, (SVCPU_R9)(r3)
+ PPC_LL r10, (SVCPU_R10)(r3)
+ PPC_LL r11, (SVCPU_R11)(r3)
+ PPC_LL r12, (SVCPU_R12)(r3)
+ PPC_LL r13, (SVCPU_R13)(r3)
+
+ PPC_LL r3, (SVCPU_R3)(r3)
+
+ RFI
+kvmppc_handler_trampoline_enter_end:
+
+
+
+/******************************************************************************
+ * *
+ * Exit code *
+ * *
+ *****************************************************************************/
+
+.global kvmppc_handler_trampoline_exit
+kvmppc_handler_trampoline_exit:
+
+ /* Register usage at this point:
+ *
+ * SPRG_SCRATCH0 = guest R13
+ * R12 = exit handler id
+ * R13 = shadow vcpu - SHADOW_VCPU_OFF [=PACA on PPC64]
+ * SVCPU.SCRATCH0 = guest R12
+ * SVCPU.SCRATCH1 = guest CR
+ *
+ */
+
+ /* Save registers */
+
+ PPC_STL r0, (SHADOW_VCPU_OFF + SVCPU_R0)(r13)
+ PPC_STL r1, (SHADOW_VCPU_OFF + SVCPU_R1)(r13)
+ PPC_STL r2, (SHADOW_VCPU_OFF + SVCPU_R2)(r13)
+ PPC_STL r3, (SHADOW_VCPU_OFF + SVCPU_R3)(r13)
+ PPC_STL r4, (SHADOW_VCPU_OFF + SVCPU_R4)(r13)
+ PPC_STL r5, (SHADOW_VCPU_OFF + SVCPU_R5)(r13)
+ PPC_STL r6, (SHADOW_VCPU_OFF + SVCPU_R6)(r13)
+ PPC_STL r7, (SHADOW_VCPU_OFF + SVCPU_R7)(r13)
+ PPC_STL r8, (SHADOW_VCPU_OFF + SVCPU_R8)(r13)
+ PPC_STL r9, (SHADOW_VCPU_OFF + SVCPU_R9)(r13)
+ PPC_STL r10, (SHADOW_VCPU_OFF + SVCPU_R10)(r13)
+ PPC_STL r11, (SHADOW_VCPU_OFF + SVCPU_R11)(r13)
+
+ /* Restore R1/R2 so we can handle faults */
+ PPC_LL r1, (SHADOW_VCPU_OFF + SVCPU_HOST_R1)(r13)
+ PPC_LL r2, (SHADOW_VCPU_OFF + SVCPU_HOST_R2)(r13)
+
+ /* Save guest PC and MSR */
+ mfsrr0 r3
+ mfsrr1 r4
+
+ PPC_STL r3, (SHADOW_VCPU_OFF + SVCPU_PC)(r13)
+ PPC_STL r4, (SHADOW_VCPU_OFF + SVCPU_SHADOW_SRR1)(r13)
+
+ /* Get scratch'ed off registers */
+ mfspr r9, SPRN_SPRG_SCRATCH0
+ PPC_LL r8, (SHADOW_VCPU_OFF + SVCPU_SCRATCH0)(r13)
+ lwz r7, (SHADOW_VCPU_OFF + SVCPU_SCRATCH1)(r13)
+
+ PPC_STL r9, (SHADOW_VCPU_OFF + SVCPU_R13)(r13)
+ PPC_STL r8, (SHADOW_VCPU_OFF + SVCPU_R12)(r13)
+ stw r7, (SHADOW_VCPU_OFF + SVCPU_CR)(r13)
+
+ /* Save more register state */
+
+ mfxer r5
+ mfdar r6
+ mfdsisr r7
+ mfctr r8
+ mflr r9
+
+ stw r5, (SHADOW_VCPU_OFF + SVCPU_XER)(r13)
+ PPC_STL r6, (SHADOW_VCPU_OFF + SVCPU_FAULT_DAR)(r13)
+ stw r7, (SHADOW_VCPU_OFF + SVCPU_FAULT_DSISR)(r13)
+ PPC_STL r8, (SHADOW_VCPU_OFF + SVCPU_CTR)(r13)
+ PPC_STL r9, (SHADOW_VCPU_OFF + SVCPU_LR)(r13)
+
+ /*
+ * In order for us to easily get the last instruction,
+ * we got the #vmexit at, we exploit the fact that the
+ * virtual layout is still the same here, so we can just
+ * ld from the guest's PC address
+ */
+
+ /* We only load the last instruction when it's safe */
+ cmpwi r12, BOOK3S_INTERRUPT_DATA_STORAGE
+ beq ld_last_inst
+ cmpwi r12, BOOK3S_INTERRUPT_PROGRAM
+ beq ld_last_inst
+
+ b no_ld_last_inst
+
+ld_last_inst:
+ /* Save off the guest instruction we're at */
+
+ /* In case lwz faults */
+ li r0, KVM_INST_FETCH_FAILED
+
+#ifdef USE_QUICK_LAST_INST
+
+ /* Set guest mode to 'jump over instruction' so if lwz faults
+ * we'll just continue at the next IP. */
+ li r9, KVM_GUEST_MODE_SKIP
+ stb r9, (SHADOW_VCPU_OFF + SVCPU_IN_GUEST)(r13)
+
+ /* 1) enable paging for data */
+ mfmsr r9
+ ori r11, r9, MSR_DR /* Enable paging for data */
+ mtmsr r11
+ sync
+ /* 2) fetch the instruction */
+ lwz r0, 0(r3)
+ /* 3) disable paging again */
+ mtmsr r9
+ sync
+
+#endif
+ stw r0, (SHADOW_VCPU_OFF + SVCPU_LAST_INST)(r13)
+
+no_ld_last_inst:
+
+ /* Unset guest mode */
+ li r9, KVM_GUEST_MODE_NONE
+ stb r9, (SHADOW_VCPU_OFF + SVCPU_IN_GUEST)(r13)
+
+ /* Switch back to host MMU */
+ LOAD_HOST_SEGMENTS
+
+ /* Register usage at this point:
+ *
+ * R1 = host R1
+ * R2 = host R2
+ * R12 = exit handler id
+ * R13 = shadow vcpu - SHADOW_VCPU_OFF [=PACA on PPC64]
+ * SVCPU.* = guest *
+ *
+ */
+
+ /* RFI into the highmem handler */
+ mfmsr r7
+ ori r7, r7, MSR_IR|MSR_DR|MSR_RI|MSR_ME /* Enable paging */
+ mtsrr1 r7
+ /* Load highmem handler address */
+ PPC_LL r8, (SHADOW_VCPU_OFF + SVCPU_VMHANDLER)(r13)
+ mtsrr0 r8
+
+ RFI
+kvmppc_handler_trampoline_exit_end: