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linux-stable/arch/powerpc/kvm/book3s_64_entry.S

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KVM: PPC: Book3S 64: move KVM interrupt entry to a common entry point Rather than bifurcate the call depending on whether or not HV is possible, and have the HV entry test for PR, just make a single common point which does the demultiplexing. This makes it simpler to add another type of exit handler. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Acked-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-2-npiggin@gmail.com
2021-05-28 09:07:21 +00:00
/* SPDX-License-Identifier: GPL-2.0-only */
#include <asm/asm-offsets.h>
#include <asm/cache.h>
KVM: PPC: Book3S 64: Move GUEST_MODE_SKIP test into KVM Move the GUEST_MODE_SKIP logic into KVM code. This is quite a KVM internal detail that has no real need to be in common handlers. Add a comment explaining the what and why of KVM "skip" interrupts. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-3-npiggin@gmail.com
2021-05-28 09:07:22 +00:00
#include <asm/exception-64s.h>
KVM: PPC: Book3S 64: move KVM interrupt entry to a common entry point Rather than bifurcate the call depending on whether or not HV is possible, and have the HV entry test for PR, just make a single common point which does the demultiplexing. This makes it simpler to add another type of exit handler. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Acked-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-2-npiggin@gmail.com
2021-05-28 09:07:21 +00:00
#include <asm/kvm_asm.h>
#include <asm/kvm_book3s_asm.h>
#include <asm/ppc_asm.h>
#include <asm/reg.h>
/*
KVM: PPC: Book3S 64: add hcall interrupt handler Add a separate hcall entry point. This can be used to deal with the different calling convention. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-4-npiggin@gmail.com
2021-05-28 09:07:23 +00:00
* These are branched to from interrupt handlers in exception-64s.S which set
KVM: PPC: Book3S 64: move KVM interrupt entry to a common entry point Rather than bifurcate the call depending on whether or not HV is possible, and have the HV entry test for PR, just make a single common point which does the demultiplexing. This makes it simpler to add another type of exit handler. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Acked-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-2-npiggin@gmail.com
2021-05-28 09:07:21 +00:00
* IKVM_REAL or IKVM_VIRT, if HSTATE_IN_GUEST was found to be non-zero.
*/
KVM: PPC: Book3S 64: Minimise hcall handler calling convention differences This sets up the same calling convention from interrupt entry to KVM interrupt handler for system calls as exists for other interrupt types. This is a better API, it uses a save area rather than SPR, and it has more registers free to use. Using a single common API helps maintain it, and it becomes easier to use in C in a later patch. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-8-npiggin@gmail.com
2021-05-28 09:07:27 +00:00
/*
* This is a hcall, so register convention is as
* Documentation/powerpc/papr_hcalls.rst.
*
* This may also be a syscall from PR-KVM userspace that is to be
* reflected to the PR guest kernel, so registers may be set up for
* a system call rather than hcall. We don't currently clobber
* anything here, but the 0xc00 handler has already clobbered CTR
* and CR0, so PR-KVM can not support a guest kernel that preserves
* those registers across its system calls.
*
* The state of registers is as kvmppc_interrupt, except CFAR is not
* saved, R13 is not in SCRATCH0, and R10 does not contain the trap.
*/
KVM: PPC: Book3S 64: add hcall interrupt handler Add a separate hcall entry point. This can be used to deal with the different calling convention. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-4-npiggin@gmail.com
2021-05-28 09:07:23 +00:00
.global kvmppc_hcall
.balign IFETCH_ALIGN_BYTES
kvmppc_hcall:
KVM: PPC: Book3S 64: Minimise hcall handler calling convention differences This sets up the same calling convention from interrupt entry to KVM interrupt handler for system calls as exists for other interrupt types. This is a better API, it uses a save area rather than SPR, and it has more registers free to use. Using a single common API helps maintain it, and it becomes easier to use in C in a later patch. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-8-npiggin@gmail.com
2021-05-28 09:07:27 +00:00
ld r10,PACA_EXGEN+EX_R13(r13)
SET_SCRATCH0(r10)
li r10,0xc00
/* Now we look like kvmppc_interrupt */
li r11,PACA_EXGEN
b .Lgot_save_area
KVM: PPC: Book3S 64: add hcall interrupt handler Add a separate hcall entry point. This can be used to deal with the different calling convention. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-4-npiggin@gmail.com
2021-05-28 09:07:23 +00:00
KVM: PPC: Book3S 64: Move interrupt early register setup to KVM Like the earlier patch for hcalls, KVM interrupt entry requires a different calling convention than the Linux interrupt handlers set up. Move the code that converts from one to the other into KVM. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-6-npiggin@gmail.com
2021-05-28 09:07:25 +00:00
/*
* KVM interrupt entry occurs after GEN_INT_ENTRY runs, and follows that
* call convention:
*
* guest R9-R13, CTR, CFAR, PPR saved in PACA EX_xxx save area
* guest (H)DAR, (H)DSISR are also in the save area for relevant interrupts
* guest R13 also saved in SCRATCH0
* R13 = PACA
* R11 = (H)SRR0
* R12 = (H)SRR1
* R9 = guest CR
* PPR is set to medium
*
* With the addition for KVM:
* R10 = trap vector
*/
KVM: PPC: Book3S 64: move KVM interrupt entry to a common entry point Rather than bifurcate the call depending on whether or not HV is possible, and have the HV entry test for PR, just make a single common point which does the demultiplexing. This makes it simpler to add another type of exit handler. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Acked-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-2-npiggin@gmail.com
2021-05-28 09:07:21 +00:00
.global kvmppc_interrupt
.balign IFETCH_ALIGN_BYTES
kvmppc_interrupt:
KVM: PPC: Book3S 64: Move interrupt early register setup to KVM Like the earlier patch for hcalls, KVM interrupt entry requires a different calling convention than the Linux interrupt handlers set up. Move the code that converts from one to the other into KVM. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-6-npiggin@gmail.com
2021-05-28 09:07:25 +00:00
li r11,PACA_EXGEN
cmpdi r10,0x200
KVM: PPC: Book3S 64: Minimise hcall handler calling convention differences This sets up the same calling convention from interrupt entry to KVM interrupt handler for system calls as exists for other interrupt types. This is a better API, it uses a save area rather than SPR, and it has more registers free to use. Using a single common API helps maintain it, and it becomes easier to use in C in a later patch. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-8-npiggin@gmail.com
2021-05-28 09:07:27 +00:00
bgt+ .Lgot_save_area
KVM: PPC: Book3S 64: Move interrupt early register setup to KVM Like the earlier patch for hcalls, KVM interrupt entry requires a different calling convention than the Linux interrupt handlers set up. Move the code that converts from one to the other into KVM. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-6-npiggin@gmail.com
2021-05-28 09:07:25 +00:00
li r11,PACA_EXMC
KVM: PPC: Book3S 64: Minimise hcall handler calling convention differences This sets up the same calling convention from interrupt entry to KVM interrupt handler for system calls as exists for other interrupt types. This is a better API, it uses a save area rather than SPR, and it has more registers free to use. Using a single common API helps maintain it, and it becomes easier to use in C in a later patch. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-8-npiggin@gmail.com
2021-05-28 09:07:27 +00:00
beq .Lgot_save_area
KVM: PPC: Book3S 64: Move interrupt early register setup to KVM Like the earlier patch for hcalls, KVM interrupt entry requires a different calling convention than the Linux interrupt handlers set up. Move the code that converts from one to the other into KVM. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-6-npiggin@gmail.com
2021-05-28 09:07:25 +00:00
li r11,PACA_EXNMI
KVM: PPC: Book3S 64: Minimise hcall handler calling convention differences This sets up the same calling convention from interrupt entry to KVM interrupt handler for system calls as exists for other interrupt types. This is a better API, it uses a save area rather than SPR, and it has more registers free to use. Using a single common API helps maintain it, and it becomes easier to use in C in a later patch. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-8-npiggin@gmail.com
2021-05-28 09:07:27 +00:00
.Lgot_save_area:
add r11,r11,r13
KVM: PPC: Book3S 64: Move interrupt early register setup to KVM Like the earlier patch for hcalls, KVM interrupt entry requires a different calling convention than the Linux interrupt handlers set up. Move the code that converts from one to the other into KVM. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-6-npiggin@gmail.com
2021-05-28 09:07:25 +00:00
BEGIN_FTR_SECTION
ld r12,EX_CFAR(r11)
std r12,HSTATE_CFAR(r13)
END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
ld r12,EX_CTR(r11)
mtctr r12
BEGIN_FTR_SECTION
ld r12,EX_PPR(r11)
std r12,HSTATE_PPR(r13)
END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
ld r12,EX_R12(r11)
std r12,HSTATE_SCRATCH0(r13)
sldi r12,r9,32
or r12,r12,r10
ld r9,EX_R9(r11)
ld r10,EX_R10(r11)
ld r11,EX_R11(r11)
KVM: PPC: Book3S 64: move KVM interrupt entry to a common entry point Rather than bifurcate the call depending on whether or not HV is possible, and have the HV entry test for PR, just make a single common point which does the demultiplexing. This makes it simpler to add another type of exit handler. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Acked-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-2-npiggin@gmail.com
2021-05-28 09:07:21 +00:00
/*
KVM: PPC: Book3S 64: Move interrupt early register setup to KVM Like the earlier patch for hcalls, KVM interrupt entry requires a different calling convention than the Linux interrupt handlers set up. Move the code that converts from one to the other into KVM. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-6-npiggin@gmail.com
2021-05-28 09:07:25 +00:00
* Hcalls and other interrupts come here after normalising register
* contents and save locations:
*
KVM: PPC: Book3S 64: move KVM interrupt entry to a common entry point Rather than bifurcate the call depending on whether or not HV is possible, and have the HV entry test for PR, just make a single common point which does the demultiplexing. This makes it simpler to add another type of exit handler. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Acked-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-2-npiggin@gmail.com
2021-05-28 09:07:21 +00:00
* R12 = (guest CR << 32) | interrupt vector
* R13 = PACA
KVM: PPC: Book3S 64: Move interrupt early register setup to KVM Like the earlier patch for hcalls, KVM interrupt entry requires a different calling convention than the Linux interrupt handlers set up. Move the code that converts from one to the other into KVM. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-6-npiggin@gmail.com
2021-05-28 09:07:25 +00:00
* guest R12 saved in shadow HSTATE_SCRATCH0
KVM: PPC: Book3S 64: move KVM interrupt entry to a common entry point Rather than bifurcate the call depending on whether or not HV is possible, and have the HV entry test for PR, just make a single common point which does the demultiplexing. This makes it simpler to add another type of exit handler. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Acked-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-2-npiggin@gmail.com
2021-05-28 09:07:21 +00:00
* guest R13 saved in SPRN_SCRATCH0
*/
std r9,HSTATE_SCRATCH2(r13)
lbz r9,HSTATE_IN_GUEST(r13)
KVM: PPC: Book3S 64: Move GUEST_MODE_SKIP test into KVM Move the GUEST_MODE_SKIP logic into KVM code. This is quite a KVM internal detail that has no real need to be in common handlers. Add a comment explaining the what and why of KVM "skip" interrupts. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-3-npiggin@gmail.com
2021-05-28 09:07:22 +00:00
cmpwi r9,KVM_GUEST_MODE_SKIP
beq- .Lmaybe_skip
.Lno_skip:
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
KVM: PPC: Book3S 64: move KVM interrupt entry to a common entry point Rather than bifurcate the call depending on whether or not HV is possible, and have the HV entry test for PR, just make a single common point which does the demultiplexing. This makes it simpler to add another type of exit handler. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Acked-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-2-npiggin@gmail.com
2021-05-28 09:07:21 +00:00
#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
cmpwi r9,KVM_GUEST_MODE_GUEST
beq kvmppc_interrupt_pr
#endif
b kvmppc_interrupt_hv
#else
b kvmppc_interrupt_pr
#endif
KVM: PPC: Book3S 64: Move GUEST_MODE_SKIP test into KVM Move the GUEST_MODE_SKIP logic into KVM code. This is quite a KVM internal detail that has no real need to be in common handlers. Add a comment explaining the what and why of KVM "skip" interrupts. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-3-npiggin@gmail.com
2021-05-28 09:07:22 +00:00
/*
* "Skip" interrupts are part of a trick KVM uses a with hash guests to load
* the faulting instruction in guest memory from the the hypervisor without
* walking page tables.
*
* When the guest takes a fault that requires the hypervisor to load the
* instruction (e.g., MMIO emulation), KVM is running in real-mode with HV=1
* and the guest MMU context loaded. It sets KVM_GUEST_MODE_SKIP, and sets
* MSR[DR]=1 while leaving MSR[IR]=0, so it continues to fetch HV instructions
* but loads and stores will access the guest context. This is used to load
* the faulting instruction using the faulting guest effective address.
*
* However the guest context may not be able to translate, or it may cause a
* machine check or other issue, which results in a fault in the host
* (even with KVM-HV).
*
* These faults come here because KVM_GUEST_MODE_SKIP was set, so if they
* are (or are likely) caused by that load, the instruction is skipped by
* just returning with the PC advanced +4, where it is noticed the load did
* not execute and it goes to the slow path which walks the page tables to
* read guest memory.
*/
.Lmaybe_skip:
cmpwi r12,BOOK3S_INTERRUPT_MACHINE_CHECK
beq 1f
cmpwi r12,BOOK3S_INTERRUPT_DATA_STORAGE
beq 1f
cmpwi r12,BOOK3S_INTERRUPT_DATA_SEGMENT
beq 1f
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
/* HSRR interrupts get 2 added to interrupt number */
cmpwi r12,BOOK3S_INTERRUPT_H_DATA_STORAGE | 0x2
beq 2f
#endif
b .Lno_skip
1: mfspr r9,SPRN_SRR0
addi r9,r9,4
mtspr SPRN_SRR0,r9
ld r12,HSTATE_SCRATCH0(r13)
ld r9,HSTATE_SCRATCH2(r13)
GET_SCRATCH0(r13)
RFI_TO_KERNEL
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
2: mfspr r9,SPRN_HSRR0
addi r9,r9,4
mtspr SPRN_HSRR0,r9
ld r12,HSTATE_SCRATCH0(r13)
ld r9,HSTATE_SCRATCH2(r13)
GET_SCRATCH0(r13)
HRFI_TO_KERNEL
#endif
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