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KVM: PPC: Book3S: 64-bit CONFIG_RELOCATABLE support for interrupts
64-bit Book3S exception handlers must find the dynamic kernel base to add to the target address when branching beyond __end_interrupts, in order to support kernel running at non-0 physical address. Support this in KVM by branching with CTR, similarly to regular interrupt handlers. The guest CTR saved in HSTATE_SCRATCH1 and restored after the branch. Without this, the host kernel hangs and crashes randomly when it is running at a non-0 address and a KVM guest is started. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin
Michael Ellerman
parent
7ede531773
commit
a97a65d53d
4 changed files with 58 additions and 8 deletions
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@ -97,6 +97,15 @@
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ld reg,PACAKBASE(r13); \
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ori reg,reg,(ABS_ADDR(label))@l;
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/*
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* Branches from unrelocated code (e.g., interrupts) to labels outside
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* head-y require >64K offsets.
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*/
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#define __LOAD_FAR_HANDLER(reg, label) \
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ld reg,PACAKBASE(r13); \
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ori reg,reg,(ABS_ADDR(label))@l; \
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addis reg,reg,(ABS_ADDR(label))@h;
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/* Exception register prefixes */
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#define EXC_HV H
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#define EXC_STD
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@ -227,12 +236,40 @@ END_FTR_SECTION_NESTED(ftr,ftr,943)
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mtctr reg; \
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bctr
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/*
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* KVM requires __LOAD_FAR_HANDLER.
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*
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* __BRANCH_TO_KVM_EXIT branches are also a special case because they
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* explicitly use r9 then reload it from PACA before branching. Hence
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* the double-underscore.
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*/
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#define __BRANCH_TO_KVM_EXIT(area, label) \
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mfctr r9; \
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std r9,HSTATE_SCRATCH1(r13); \
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__LOAD_FAR_HANDLER(r9, label); \
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mtctr r9; \
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ld r9,area+EX_R9(r13); \
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bctr
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#define BRANCH_TO_KVM(reg, label) \
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__LOAD_FAR_HANDLER(reg, label); \
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mtctr reg; \
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bctr
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#else
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#define BRANCH_TO_COMMON(reg, label) \
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b label
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#define BRANCH_TO_KVM(reg, label) \
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b label
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#define __BRANCH_TO_KVM_EXIT(area, label) \
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ld r9,area+EX_R9(r13); \
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b label
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#endif
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#define __KVM_HANDLER(area, h, n) \
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BEGIN_FTR_SECTION_NESTED(947) \
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ld r10,area+EX_CFAR(r13); \
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@ -246,8 +283,8 @@ END_FTR_SECTION_NESTED(ftr,ftr,943)
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std r12,HSTATE_SCRATCH0(r13); \
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sldi r12,r9,32; \
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ori r12,r12,(n); \
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ld r9,area+EX_R9(r13); \
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b kvmppc_interrupt
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/* This reloads r9 before branching to kvmppc_interrupt */ \
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__BRANCH_TO_KVM_EXIT(area, kvmppc_interrupt)
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#define __KVM_HANDLER_SKIP(area, h, n) \
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cmpwi r10,KVM_GUEST_MODE_SKIP; \
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@ -260,8 +297,8 @@ END_FTR_SECTION_NESTED(ftr,ftr,943)
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std r12,HSTATE_SCRATCH0(r13); \
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sldi r12,r9,32; \
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ori r12,r12,(n); \
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ld r9,area+EX_R9(r13); \
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b kvmppc_interrupt; \
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/* This reloads r9 before branching to kvmppc_interrupt */ \
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__BRANCH_TO_KVM_EXIT(area, kvmppc_interrupt); \
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89: mtocrf 0x80,r9; \
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ld r9,area+EX_R9(r13); \
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ld r10,area+EX_R10(r13); \
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@ -142,7 +142,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
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lbz r0,HSTATE_HWTHREAD_REQ(r13)
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cmpwi r0,0
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beq 1f
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b kvm_start_guest
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BRANCH_TO_KVM(r10, kvm_start_guest)
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1:
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#endif
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@ -1060,15 +1060,16 @@ kvmppc_interrupt_hv:
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* R12 = (guest CR << 32) | interrupt vector
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* R13 = PACA
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* guest R12 saved in shadow VCPU SCRATCH0
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* guest CTR saved in shadow VCPU SCRATCH1 if RELOCATABLE
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* guest R13 saved in SPRN_SCRATCH0
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*/
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std r9, HSTATE_SCRATCH1(r13)
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std r9, HSTATE_SCRATCH2(r13)
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lbz r9, HSTATE_IN_GUEST(r13)
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cmpwi r9, KVM_GUEST_MODE_HOST_HV
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beq kvmppc_bad_host_intr
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#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
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cmpwi r9, KVM_GUEST_MODE_GUEST
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ld r9, HSTATE_SCRATCH1(r13)
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ld r9, HSTATE_SCRATCH2(r13)
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beq kvmppc_interrupt_pr
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#endif
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/* We're now back in the host but in guest MMU context */
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@ -1088,7 +1089,7 @@ kvmppc_interrupt_hv:
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std r6, VCPU_GPR(R6)(r9)
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std r7, VCPU_GPR(R7)(r9)
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std r8, VCPU_GPR(R8)(r9)
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ld r0, HSTATE_SCRATCH1(r13)
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ld r0, HSTATE_SCRATCH2(r13)
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std r0, VCPU_GPR(R9)(r9)
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std r10, VCPU_GPR(R10)(r9)
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std r11, VCPU_GPR(R11)(r9)
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@ -1151,7 +1152,12 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
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11: stw r3,VCPU_HEIR(r9)
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/* these are volatile across C function calls */
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#ifdef CONFIG_RELOCATABLE
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ld r3, HSTATE_SCRATCH1(r13)
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mtctr r3
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#else
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mfctr r3
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#endif
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mfxer r4
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std r3, VCPU_CTR(r9)
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std r4, VCPU_XER(r9)
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@ -175,9 +175,16 @@ kvmppc_interrupt_pr:
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* R12 = (guest CR << 32) | exit handler id
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* R13 = PACA
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* HSTATE.SCRATCH0 = guest R12
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* HSTATE.SCRATCH1 = guest CTR if RELOCATABLE
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*/
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#ifdef CONFIG_PPC64
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/* Match 32-bit entry */
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#ifdef CONFIG_RELOCATABLE
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std r9, HSTATE_SCRATCH2(r13)
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ld r9, HSTATE_SCRATCH1(r13)
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mtctr r9
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ld r9, HSTATE_SCRATCH2(r13)
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#endif
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rotldi r12, r12, 32 /* Flip R12 halves for stw */
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stw r12, HSTATE_SCRATCH1(r13) /* CR is now in the low half */
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srdi r12, r12, 32 /* shift trap into low half */
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