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Fri, 18 Sep 2026 13:31:15 +0000 (GMT) Received: from tuxmaker.lnxne.boe (unknown [9.87.85.9]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 18 Sep 2026 13:31:15 +0000 (GMT) From: Steffen Eiden To: kvm@vger.kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org Cc: Alexander Gordeev , Andreas Grapentin , Arnd Bergmann , Catalin Marinas , Christian Borntraeger , Claudio Imbrenda , David Hildenbrand , Friedrich Welter , Fuad Tabba , Gautam Gala , Hariharan Mari , Heiko Carstens , Hendrik Brueckner , Ilya Leoshkevich , Janosch Frank , Joey Gouly , Marc Zyngier , Nico Boehr , Nina Schoetterl-Glausch , Oliver Upton , Paolo Bonzini , Suzuki K Poulose , Sven Schnelle , Ulrich Weigand , Vasily Gorbik , Will Deacon , Zenghui Yu Subject: [PATCH v8 20/29] s390: Introduce Start Arm Execution instruction Date: Fri, 18 Sep 2026 15:30:57 +0200 Message-ID: <20260918133107.1042730-21-seiden@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260918133107.1042730-1-seiden@linux.ibm.com> References: <20260918133107.1042730-1-seiden@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-GUID: IEVhVmBpA1jc5d-_GK7vOGB9NrfqqidR X-Proofpoint-Spam-Info: AW1haW4tMjYwOTE4MDE4NCBTYWx0ZWRfX/f89X5ytzz26 iztav76V3YIXrypgTRieWtU/tYjRJEihCLfysYkLVPJFPWtK2jPk+qF+scPHtTXacCenhBAVPxy mtzqRcneAEFutIhvfTX20nueNL+A7c0= X-Authority-Analysis: v=2.4 cv=cvgOAF4i c=1 sm=1 tr=0 ts=6aad3d2c cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VnNF1IyMAAAA:8 a=D7HF9d94yUUfLUezzdoA:9 X-Proofpoint-ORIG-GUID: vQEt_WSTqkSk_mvxOUD2nPTSI9fJFCWw X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTE4MDE4NCBTYWx0ZWRfX5VTFoRBA5hIF btvRL5wdFR3wTzH2Uc+oYxw+nUVYzknJfQ1bqvCDlduAPXz+tVZjEVRIui6KtFe7NM4XqKCUEJu +AMSJmRpVYq0GsZiucz5Vha2nxjnCAxsdAmG4uO/nwF1ZEPCF3Tu2d3BrjiNjsiDmqWDavUXeq2 to/apKYsZWpMkQn2V/TAvKRCckIsADFivHsPVL003hGMRb3JGIcWcKuwDil6N9/I8clyqzraVHj g5U17lPWY5Ba2IwyKKDNWU/Y8ql3IRqzidXp2hMJqRJdjfzT5D7DRt6R9wxgbR6mRPSa53EhgBd WEvtEwSe3tibCwYkKgJZPph3sEgFRfjpxwCEmE6pyJ1KYvwqGgM+QiybPtXIXMHovlD67rowQCA xdWZL3CDNcKHg17hWu422Z//XSAv3R+I8VTIX/Y9/uzZPmAUy8aiUYsITUY4T17ajnsO9LxIstO xaQnKYi3+CJogGtv68Q== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-18_03,2026-09-16_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 lowpriorityscore=0 clxscore=1015 priorityscore=1501 suspectscore=0 bulkscore=0 impostorscore=0 phishscore=0 spamscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2609040000 definitions=main-2609180184 The Start Arm Execution (SAE) instruction is the centerpiece for executing arm64 (KVM) guests on s390. Its purpose is, similar to SIE, to enable accelerated execution of arm64 virtual machines. SAE expects the physical address of a control block as the only argument. The host is responsible to save & restore - GPRs 0-13 - access register 0-15 - breaking event register (BEAR) - vector/floating point registers between SAE executions to guarantee host consistency. GPRs and BEAR are save and restores in the asm functions. The other register are handled in within C code. Access registers are handled in a later patch and SVEs will be handled when they are introduced in a future series. Most arm64 registers are handled by a satellite block called save_area. Some registers, frequently used by hypervisors, are placed into the SAE control block itself. Enlighten asm/kvm_host_types.h for the new header variant. The new header is chosen instead of asm/kvm_host_s390_types.h if KVM_S390_ARM64 is defined. Co-developed-by: Andreas Grapentin Signed-off-by: Andreas Grapentin Co-developed-by: Nina Schoetterl-Glausch Signed-off-by: Nina Schoetterl-Glausch Signed-off-by: Steffen Eiden --- arch/s390/include/asm/asm-prototypes.h | 1 + arch/s390/include/asm/kvm_host_arm64_types.h | 124 +++++++++++++++++++ arch/s390/include/asm/kvm_host_types.h | 4 + arch/s390/include/asm/sae.h | 58 +++++++++ arch/s390/include/asm/stacktrace.h | 5 + arch/s390/kernel/asm-offsets.c | 1 + arch/s390/kernel/entry.S | 22 ++++ arch/s390/tools/opcodes.txt | 3 + 8 files changed, 218 insertions(+) create mode 100644 arch/s390/include/asm/kvm_host_arm64_types.h create mode 100644 arch/s390/include/asm/sae.h diff --git a/arch/s390/include/asm/asm-prototypes.h b/arch/s390/include/asm/asm-prototypes.h index d4da4436d02b..faa2afb259a1 100644 --- a/arch/s390/include/asm/asm-prototypes.h +++ b/arch/s390/include/asm/asm-prototypes.h @@ -6,6 +6,7 @@ #include #include #include +#include #include #endif /* _ASM_S390_PROTOTYPES_H */ diff --git a/arch/s390/include/asm/kvm_host_arm64_types.h b/arch/s390/include/asm/kvm_host_arm64_types.h new file mode 100644 index 000000000000..8783a66d3029 --- /dev/null +++ b/arch/s390/include/asm/kvm_host_arm64_types.h @@ -0,0 +1,124 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef ASM_KVM_HOST_ARM64_TYPES_H +#define ASM_KVM_HOST_ARM64_TYPES_H + +#include +#include +#include +#include +#include + +struct kvm_sae_block { + u64 _0000[16]; /* 0x0000 */ +#define SAE_ICPTR_SPURIOUS 0x00 +#define SAE_ICPTR_VALIDITY 0x01 +#define SAE_ICPTR_HOST_ACCESS_EXCEPTION 0x02 +#define SAE_ICPTR_SYNCHRONOUS_EXCEPTION 0x03 +#define SAE_ICPTR_TIMER 0x04 +#define SAE_ICPTR_PE_INTERCOMM 0x05 +#define SAE_ICPTR_GUEST_ADDRESS_SIZE 0x06 +#define SAE_ICPTR_STOP 0x07 +#define SAE_ICPTR_MIO_ADDRESS 0x08 +#define SAE_ICPTR_PMU 0x09 +#define SAE_ICPTR_MAINTENANCE 0x0a + u8 icptr; /* 0x0080 */ + u8 _0081[7]; /* 0x0081 */ + u64 scad; /* 0x0088 */ + u64 _0090[16]; /* 0x0090 */ + u32 cntp_ctl; /* 0x0110 */ + u32 cntv_ctl; /* 0x0114 */ + u8 irq_ctl; /* 0x0118 */ + u8 _0119[7]; /* 0x0119 */ + struct { + u64 ich_hcr_el2; /* 0x0120 */ + u64 ich_vmcr_el2; /* 0x0128 */ + u64 ich_ap0r0_el2; /* 0x0130 */ + u64 ich_ap1r0_el2; /* 0x0138 */ + u64 _0140[2]; /* 0x0140 */ + u64 ich_lrn_el2[4]; /* 0x0150 */ + u64 _0170[4]; /* 0x0170 */ + } ic_regs; + u64 _0190[12]; /* 0x0190 */ + u64 contextidr_el1; /* 0x01f0 */ + u32 wip; /* 0x01f8 */ + u32 _01fc; /* 0x01fc */ +#define SAE_SD_FORMAT_0 0x00 + u8 sdf; /* 0x0200 */ + u8 _0201[7]; /* 0x0201 */ + u64 mso; /* 0x0208 */ + u64 msl; /* 0x0210 */ + u64 hbasce; /* 0x0218 */ + u64 _0220; /* 0x0220 */ + u64 gpto; /* 0x0228 */ + u64 ic; /* 0x0230 */ + u64 ec; /* 0x0238 */ + u64 save_area; /* 0x0240 */ + u64 _0248[7]; /* 0x0248 */ + u8 _0280[6]; /* 0x0280 */ + u16 lrcpua; /* 0x0286 */ + u64 pstate; /* 0x0288 */ + u64 pc; /* 0x0290 */ + u64 sp_el0; /* 0x0298 */ + u64 sp_el1; /* 0x02a0 */ + u64 _02a8; /* 0x02a8 */ + struct { /* 0x02b0 */ + u32 _fpcr_res0; + u32 fpcr; + }; + struct { /* 0x02b8 */ + u32 _fpsr_res0; + u32 fpsr; + }; + u16 sve_pregs[16]; /* 0x02c0 */ + u16 sve_ffr; /* 0x02e0 */ + u8 _02e2[6]; /* 0x02e2 */ + u64 _02e8[3]; /* 0x02e8 */ + + u64 gpr[31]; /* 0x0300 */ + u64 _03f8; /* 0x03f8 */ + + union { + u64 icptd[8]; /* 0x0400 */ + /* validity-interception reason; icptr 0x01 */ + u16 vir; /* 0x0400 */ + /* host access interception details; icptr 0x02 */ + struct { + u64 esr_el2; /* 0x0400 */ + u8 _0408[6]; /* 0x0408 */ + u16 pic; /* 0x040e */ + union teid teid; /* 0x0410 */ + gva_t far_el2; /* 0x0418 */ + gva_t vaddr; /* 0x0420 */ + u64 suppl; /* 0x0428 */ + u8 gltl; /* 0x0430 */ + u8 _0431[7]; /* 0x0431 */ + u64 _0438; /* 0x0438 */ + } hai; + /* exception-interception details; icptr 0x03 */ + struct { + u64 esr_el2; /* 0x0400 */ + u64 _0408[2]; /* 0x0408 */ + gva_t far_el2; /* 0x0418 */ + } trap; + /* timer-interception reason; icptr 0x04 */ +#define SAE_IR_TIMER_ID_VIRT BIT(6) +#define SAE_IR_TIMER_ID_PHYS BIT(7) + u8 tir; /* 0x0400 */ + }; + u64 _0440[376]; /* 0x0440 */ +} __packed __aligned(PAGE_SIZE); +static_assert(sizeof(struct kvm_sae_block) == PAGE_SIZE); + +struct kvm_sae_save_area { +#define SAE_SAVE_AREA_FORMAT_0 0x00 + u8 saf; /* 0x0000 */ + u8 _0001[5]; /* 0x0001 */ +#define SAE_SAS_VALID BIT(0) + u16 sas; /* 0x0006 */ + u64 sdo; /* 0x0008 */ + u64 _0010[2]; /* 0x0010 */ + u64 regs[508]; /* 0x0020 */ +} __packed __aligned(PAGE_SIZE); +static_assert(sizeof(struct kvm_sae_save_area) == PAGE_SIZE); + +#endif /* ASM_KVM_HOST_ARM64_TYPES_H */ diff --git a/arch/s390/include/asm/kvm_host_types.h b/arch/s390/include/asm/kvm_host_types.h index e5bdba07cab0..d308739ebcf5 100644 --- a/arch/s390/include/asm/kvm_host_types.h +++ b/arch/s390/include/asm/kvm_host_types.h @@ -3,6 +3,10 @@ #ifndef ASM_KVM_HOST_TYPES_H #define ASM_KVM_HOST_TYPES_H +#ifdef KVM_S390_ARM64 +#include +#else #include +#endif /* KVM_S390_ARM64 */ #endif /* ASM_KVM_HOST_TYPES_H */ diff --git a/arch/s390/include/asm/sae.h b/arch/s390/include/asm/sae.h new file mode 100644 index 000000000000..b644e65c4e37 --- /dev/null +++ b/arch/s390/include/asm/sae.h @@ -0,0 +1,58 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_S390_SAE_H +#define __ASM_S390_SAE_H + +#include +#include + +#ifndef __ASSEMBLER__ + +/* defined in arch/s390/kernel/entry.S */ +asmlinkage void __sae64a(phys_addr_t sae_block_phys); + +#include +#include + +/** + * sae64a() - Start Arm Execution + * @sae_block: pointer to the SAE control block + */ +static inline void sae64a(struct kvm_sae_block *sae_block) +{ + __sae64a(virt_to_phys(sae_block)); +} + +/** + * stiasrm() - STore and Invalidate Arm System Register Multiple + * @save_area: Pointer to SAE save area + * + * Store the guest system registers to the save area. + * The values in the guest are no longer valid. + */ +static __always_inline void stiasrm(struct kvm_sae_save_area *save_area) +{ + asm volatile( + " .insn rre,0xb9a70000,%[r1],0\n" + : "+m"(*save_area) + : [r1] "a"(save_area) + ); +} + +/** + * lasrm() - Load Arm System Register Multiple + * + * @save_area: Pointer to SAE save area + * + * Load the system registers from save_area into the guest. + */ +static __always_inline void lasrm(struct kvm_sae_save_area *save_area) +{ + asm volatile( + " .insn rre,0xb9a60000,%[r1],0\n" + : + : "m"(*save_area), [r1] "a"(save_area) + ); +} + +#endif /* !__ASSEMBLER__ */ +#endif /* __ASM_S390_SAE_H */ diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h index ac3606c3babe..2d332d7c8145 100644 --- a/arch/s390/include/asm/stacktrace.h +++ b/arch/s390/include/asm/stacktrace.h @@ -59,6 +59,7 @@ static inline bool on_stack(struct stack_info *info, struct stack_frame { union { unsigned long empty[9]; + /* SIE stack frame */ struct { unsigned long sie_control_block; unsigned long sie_savearea; @@ -68,6 +69,10 @@ struct stack_frame { unsigned long sie_guest_asce; unsigned long sie_irq; }; + /* SAE stack frame */ + struct { + unsigned long sae_bear; + }; }; unsigned long gprs[10]; unsigned long back_chain; diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c index f6dd2b67dcee..f9f9c2246074 100644 --- a/arch/s390/kernel/asm-offsets.c +++ b/arch/s390/kernel/asm-offsets.c @@ -70,6 +70,7 @@ int main(void) OFFSET(__SF_SIE_CONTROL_PHYS, stack_frame, sie_control_block_phys); OFFSET(__SF_SIE_GUEST_ASCE, stack_frame, sie_guest_asce); OFFSET(__SF_SIE_IRQ, stack_frame, sie_irq); + OFFSET(__SF_SAE_BEAR, stack_frame, sae_bear); DEFINE(STACK_FRAME_OVERHEAD, sizeof(struct stack_frame)); BLANK(); OFFSET(__SFUSER_BACKCHAIN, stack_frame_user, back_chain); diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 10dd9bbdf985..af515f2b6c11 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -245,6 +245,28 @@ EXPORT_SYMBOL(__sie64a) EXPORT_SYMBOL(sie_exit) #endif +#if IS_ENABLED(CONFIG_KVM) +/* + * __sae64a calling convention: + * %r2 pointer to sae control block physical address + */ +SYM_FUNC_START(__sae64a) + stmg %r6,%r14,__SF_GPRS(%r15) # store kernel registers + STBEAR __SF_SAE_BEAR(%r15) # save breaking event address register + .insn rre,0xb9a50000,%r2,0 # Start Arm Execution + LBEAR __SF_SAE_BEAR(%r15) # restore breaking event address register + lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers + xgr %r0,%r0 # clear guest registers to + xgr %r1,%r1 # prevent speculative use + xgr %r2,%r2 + xgr %r3,%r3 + xgr %r4,%r4 + xgr %r5,%r5 + BR_EX %r14 +SYM_FUNC_END(__sae64a) +EXPORT_SYMBOL(__sae64a) +#endif + /* * SVC interrupt handler routine. System calls are synchronous events and * are entered with interrupts disabled. diff --git a/arch/s390/tools/opcodes.txt b/arch/s390/tools/opcodes.txt index def2659f6602..0e4773c94af0 100644 --- a/arch/s390/tools/opcodes.txt +++ b/arch/s390/tools/opcodes.txt @@ -594,6 +594,9 @@ b9a0 clp RRF_U0RR b9a1 tpei RRE_RR b9a2 ptf RRE_R0 b9a4 uvc RRF_URR +b9a5 sae RRE_R0 +b9a6 lasrm RRE_R0 +b9a7 stiasrm RRE_R0 b9aa lptea RRF_RURR2 b9ab essa RRF_U0RR b9ac irbm RRE_RR -- 2.53.0