[PW_SID:1123077] RISC-V: KVM: Optimize hfence request handling for SMP guests by linux-riscv-bot · Pull Request #2239 · linux-riscv/linux

linux-riscv-bot · 2026-07-07T15:48:57Z

PR for series 1123077 applied to workflow__riscv__fixes

Name: RISC-V: KVM: Optimize hfence request handling for SMP guests
URL: https://patchwork.kernel.org/project/linux-riscv/list/?series=1123077
Version: 2

FENCE.I does not need hfence data, but it currently goes through the generic make_xfence_request() path with NULL data, incurring unnecessary per-VCPU checks. Split out a separate make_xfence_request_nodata() function to handle FENCE.I directly, and move the data validity check to the top of the generic function to avoid redundant checks. Signed-off-by: Wang Yechao <wang.yechao255@zte.com.cn> Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>

When handling hfence requests in make_xfence_request(), the current code uses a single 'actual_req' variable and a single vcpu_mask. If any VCPU fails to enqueue the hfence data (because its queue is full), the request falls back to 'fallback_req' for all VCPUs, even if other VCPUs still have available queue space. This can cause unnecessary fallback for healthy VCPUs, and more seriously, those healthy VCPUs will not process their already-enqueued hfence requests because no 'req' is set for them. As a result, their queues will quickly become full as well, degrading performance for SMP guests. Fix this by maintaining two separate bitmaps: one for VCPUs that successfully enqueued the hfence data (req_vcpu_mask) and another for those that failed (fallback_req_vcpu_mask). Then send the appropriate requests to each group. This ensures that fallback is only applied to VCPUs that actually need it, preserving the efficiency of the normal path for others. Fixes: 13acfec ("RISC-V: KVM: Add remote HFENCE functions based on VCPU requests") Signed-off-by: Wang Yechao <wang.yechao255@zte.com.cn> Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>

linux-riscv-bot · 2026-07-07T15:54:29Z

Patch 1: "[v2,1/2] RISC-V: KVM: Introduce make_xfence_request_nodata for FENCE.I requests"
build-rv32-defconfig
Desc: Builds riscv32 defconfig
Duration: 120.56 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T16:13:35Z

Patch 1: "[v2,1/2] RISC-V: KVM: Introduce make_xfence_request_nodata for FENCE.I requests"
build-rv64-clang-allmodconfig
Desc: Builds riscv64 allmodconfig with Clang, and checks for errors and added warnings
Duration: 1144.74 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T16:38:16Z

Patch 1: "[v2,1/2] RISC-V: KVM: Introduce make_xfence_request_nodata for FENCE.I requests"
build-rv64-gcc-allmodconfig
Desc: Builds riscv64 allmodconfig with GCC, and checks for errors and added warnings
Duration: 1479.62 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T16:38:39Z

Patch 1: "[v2,1/2] RISC-V: KVM: Introduce make_xfence_request_nodata for FENCE.I requests"
build-rv64-nommu-k210-defconfig
Desc: Builds riscv64 defconfig with NOMMU for K210
Duration: 20.59 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T16:39:02Z

Patch 1: "[v2,1/2] RISC-V: KVM: Introduce make_xfence_request_nodata for FENCE.I requests"
build-rv64-nommu-k210-virt
Desc: Builds riscv64 defconfig with NOMMU for the virt platform
Duration: 22.12 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T16:39:06Z

Patch 1: "[v2,1/2] RISC-V: KVM: Introduce make_xfence_request_nodata for FENCE.I requests"
checkpatch
Desc: Runs checkpatch.pl on the patch
Duration: 1.74 seconds
Result: WARNING
Output:

CHECK: Alignment should match open parenthesis
#40: FILE: arch/riscv/kvm/tlb.c:339:
+			if (vcpu->vcpu_id < hbase ||
+				vcpu->vcpu_id >= hbase + BITS_PER_LONG)

total: 0 errors, 0 warnings, 1 checks, 56 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

Commit 846d0d6dc26e ("RISC-V: KVM: Introduce make_xfence_request_nodata for FENCE.I requests") has style problems, please review.

NOTE: Ignored message types: ALLOC_SIZEOF_STRUCT CAMELCASE COMMIT_LOG_LONG_LINE GIT_COMMIT_ID MACRO_ARG_REUSE NO_AUTHOR_SIGN_OFF

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.
total: 0 errors, 0 warnings, 1 checks, 56 lines checked
CHECK: Alignment should match open parenthesis

linux-riscv-bot · 2026-07-07T16:40:32Z

Patch 1: "[v2,1/2] RISC-V: KVM: Introduce make_xfence_request_nodata for FENCE.I requests"
dtb-warn-rv64
Desc: Checks for Device Tree warnings/errors
Duration: 84.54 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T16:40:34Z

Patch 1: "[v2,1/2] RISC-V: KVM: Introduce make_xfence_request_nodata for FENCE.I requests"
header-inline
Desc: Detects static functions without inline keyword in header files
Duration: 0.23 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T16:40:36Z

Patch 1: "[v2,1/2] RISC-V: KVM: Introduce make_xfence_request_nodata for FENCE.I requests"
kdoc
Desc: Detects for kdoc errors
Duration: 0.76 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T16:40:38Z

Patch 1: "[v2,1/2] RISC-V: KVM: Introduce make_xfence_request_nodata for FENCE.I requests"
module-param
Desc: Detect module_param changes
Duration: 0.24 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T16:40:40Z

Patch 1: "[v2,1/2] RISC-V: KVM: Introduce make_xfence_request_nodata for FENCE.I requests"
verify-fixes
Desc: Verifies that the Fixes: tags exist
Duration: 0.22 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T16:40:42Z

Patch 1: "[v2,1/2] RISC-V: KVM: Introduce make_xfence_request_nodata for FENCE.I requests"
verify-signedoff
Desc: Verifies that Signed-off-by: tags are correct
Duration: 0.64 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T16:43:00Z

Patch 2: "[v2,2/2] RISC-V: KVM: Separate req and fallback_req masks in make_xfence_request"
build-rv32-defconfig
Desc: Builds riscv32 defconfig
Duration: 121.79 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T17:02:47Z

Patch 2: "[v2,2/2] RISC-V: KVM: Separate req and fallback_req masks in make_xfence_request"
build-rv64-clang-allmodconfig
Desc: Builds riscv64 allmodconfig with Clang, and checks for errors and added warnings
Duration: 1186.23 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T17:27:28Z

Patch 2: "[v2,2/2] RISC-V: KVM: Separate req and fallback_req masks in make_xfence_request"
build-rv64-gcc-allmodconfig
Desc: Builds riscv64 allmodconfig with GCC, and checks for errors and added warnings
Duration: 1478.63 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T17:27:50Z

Patch 2: "[v2,2/2] RISC-V: KVM: Separate req and fallback_req masks in make_xfence_request"
build-rv64-nommu-k210-defconfig
Desc: Builds riscv64 defconfig with NOMMU for K210
Duration: 20.44 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T17:28:14Z

Patch 2: "[v2,2/2] RISC-V: KVM: Separate req and fallback_req masks in make_xfence_request"
build-rv64-nommu-k210-virt
Desc: Builds riscv64 defconfig with NOMMU for the virt platform
Duration: 22.17 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T17:28:16Z

Patch 2: "[v2,2/2] RISC-V: KVM: Separate req and fallback_req masks in make_xfence_request"
checkpatch
Desc: Runs checkpatch.pl on the patch
Duration: 0.64 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T17:29:42Z

Patch 2: "[v2,2/2] RISC-V: KVM: Separate req and fallback_req masks in make_xfence_request"
dtb-warn-rv64
Desc: Checks for Device Tree warnings/errors
Duration: 84.52 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T17:29:44Z

Patch 2: "[v2,2/2] RISC-V: KVM: Separate req and fallback_req masks in make_xfence_request"
header-inline
Desc: Detects static functions without inline keyword in header files
Duration: 0.22 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T17:29:46Z

Patch 2: "[v2,2/2] RISC-V: KVM: Separate req and fallback_req masks in make_xfence_request"
kdoc
Desc: Detects for kdoc errors
Duration: 0.75 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T17:29:48Z

Patch 2: "[v2,2/2] RISC-V: KVM: Separate req and fallback_req masks in make_xfence_request"
module-param
Desc: Detect module_param changes
Duration: 0.24 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T17:29:49Z

Patch 2: "[v2,2/2] RISC-V: KVM: Separate req and fallback_req masks in make_xfence_request"
verify-fixes
Desc: Verifies that the Fixes: tags exist
Duration: 0.25 seconds
Result: PASS

linux-riscv-bot · 2026-07-07T17:29:51Z

Patch 2: "[v2,2/2] RISC-V: KVM: Separate req and fallback_req masks in make_xfence_request"
verify-signedoff
Desc: Verifies that Signed-off-by: tags are correct
Duration: 0.26 seconds
Result: PASS

yechao-w added 2 commits July 7, 2026 15:48

linux-riscv-bot closed this Jul 8, 2026

linux-riscv-bot deleted the pw1123077 branch July 8, 2026 05:09

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