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. Reviewed-by: Alexey Kardashevskiy <aik@xxxxxxxxx> Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx> --- arch/powerpc/kernel/exceptions-64s.S | 21 +++++++++- arch/powerpc/kvm/book3s_64_entry.S | 61 ++++++++++++---------------- 2 files changed, 45 insertions(+), 37 deletions(-) diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index cd1731642b12..24c54b6fb3d7 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -1892,8 +1892,27 @@ EXC_VIRT_END(system_call, 0x4c00, 0x100) #ifdef CONFIG_KVM_BOOK3S_64_HANDLER TRAMP_REAL_BEGIN(kvm_hcall) + std r9,PACA_EXGEN+EX_R9(r13) + std r11,PACA_EXGEN+EX_R11(r13) + std r12,PACA_EXGEN+EX_R12(r13) + mfcr r9 mfctr r10 - SET_SCRATCH0(r10) /* Save r13 in SCRATCH0 */ + std r10,PACA_EXGEN+EX_R13(r13) + li r10,0 + std r10,PACA_EXGEN+EX_CFAR(r13) + std r10,PACA_EXGEN+EX_CTR(r13) + /* + * Save the PPR (on systems that support it) before changing to + * HMT_MEDIUM. That allows the KVM code to save that value into the + * guest state (it is the guest's PPR value). + */ +BEGIN_FTR_SECTION + mfspr r10,SPRN_PPR + std r10,PACA_EXGEN+EX_PPR(r13) +END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) + + HMT_MEDIUM + #ifdef CONFIG_RELOCATABLE /* * Requires __LOAD_FAR_HANDLER beause kvmppc_hcall lives diff --git a/arch/powerpc/kvm/book3s_64_entry.S b/arch/powerpc/kvm/book3s_64_entry.S index 66170ea85bc2..a01046202eef 100644 --- a/arch/powerpc/kvm/book3s_64_entry.S +++ b/arch/powerpc/kvm/book3s_64_entry.S @@ -11,40 +11,30 @@ * These are branched to from interrupt handlers in exception-64s.S which set * IKVM_REAL or IKVM_VIRT, if HSTATE_IN_GUEST was found to be non-zero. */ + +/* + * 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. + */ .global kvmppc_hcall .balign IFETCH_ALIGN_BYTES kvmppc_hcall: - /* - * This is a hcall, so register convention is as - * Documentation/powerpc/papr_hcalls.rst, with these additions: - * R13 = PACA - * guest R13 saved in SPRN_SCRATCH0 - * R10 = free - * guest r10 saved in PACA_EXGEN - * - * 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. - */ - /* - * Save the PPR (on systems that support it) before changing to - * HMT_MEDIUM. That allows the KVM code to save that value into the - * guest state (it is the guest's PPR value). - */ -BEGIN_FTR_SECTION - mfspr r10,SPRN_PPR - std r10,HSTATE_PPR(r13) -END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) - HMT_MEDIUM - mfcr r10 - std r12,HSTATE_SCRATCH0(r13) - sldi r12,r10,32 - ori r12,r12,0xc00 - ld r10,PACA_EXGEN+EX_R10(r13) - b do_kvm_interrupt + 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 interrupt entry occurs after GEN_INT_ENTRY runs, and follows that @@ -67,12 +57,12 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) kvmppc_interrupt: li r11,PACA_EXGEN cmpdi r10,0x200 - bgt+ 1f + bgt+ .Lgot_save_area li r11,PACA_EXMC - beq 1f + beq .Lgot_save_area li r11,PACA_EXNMI -1: add r11,r11,r13 - +.Lgot_save_area: + add r11,r11,r13 BEGIN_FTR_SECTION ld r12,EX_CFAR(r11) std r12,HSTATE_CFAR(r13) @@ -91,7 +81,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) ld r10,EX_R10(r11) ld r11,EX_R11(r11) -do_kvm_interrupt: /* * Hcalls and other interrupts come here after normalising register * contents and save locations: -- 2.23.0
