From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-210.mta0.migadu.com [91.218.175.210]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8AC4233F5BC for ; Sat, 15 Aug 2026 10:06:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.210 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786788411; cv=none; b=rFp/Iu2D/sOI0qs5MFGRN7+NWDRphvdog3iNVtWvdASCHpjO1pgBU3t6eUDAf7ZAU7ahp5sbuY++DC7Bkp6ae1GqD4REd42aZwo+UoJMUxOzxZg8tuCzJZyhgnOA8pY69MfwMyQPSHEu1cSwUIYBGbEE+OsOoj5UkcHeAF7pyPQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786788411; c=relaxed/simple; bh=V5XVfLEQRMIUdVa1VN5yR7RiRSe4x0lsprp3ClMwZ+c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HJ5XuMPvUgtJo7vIWQUrNrJ73gdCLsXwtvs+IwxObRMl9uprh6ffY9AbMPKGo+CDZMIny5BpoB22lL5OL54TM/zw+PHynPxHlXnMtprT/AhVXaATO/LS13eGKjPf/X1fnEkJqc/okmd+m9UNS0bP/GaTEpe3EaXd6nilhDgOnb4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=Pw5IeT68; arc=none smtp.client-ip=91.218.175.210 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="Pw5IeT68" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=V5XVfLEQRMIUdVa1VN5yR7RiRSe4x0lsprp3ClMwZ+c=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1786788407; v=1; x=1787393207; b=Pw5IeT68zZDgXeePaxQkEEnXXexNKsckbJio3dp3pidhD9GwsOrhY+PUYNHPgD8KSqJ7oTBO OjnTyNa0uGPyGH6NC+1hfoONLGZinX31u4cYld1pJOja1MvCMjaebEglmVlSXIyDTkYEKNWNN+u YKPvBoTzRZdtig4p/dbz+i8Y= X-Envelope-To: linux-kernel@vger.kernel.org Received: from localhost.localdomain (2408:823d:2011:2c0:e810:54f9:f0a3:99d) by smtp.migadu.com with ESMTPS id e58b234c548717e0; Sat, 15 Aug 2026 10:06:47 +0000 X-Migadu-Flow: FLOW_OUT From: Jinyu Tang To: Anup Patel , Anup Patel , Atish Patra Cc: kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Paolo Bonzini , Sean Christopherson , Shuah Khan , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Andrew Jones , Conor Dooley , Yong-Xuan Wang , Nutty Liu , Yifei Jiang , Jinyu Tang , Jinyu Tang Subject: [PATCH v4 3/5] KVM: riscv: Implement KVM_PRE_FAULT_MEMORY Date: Sat, 15 Aug 2026 06:06:36 -0400 Message-ID: <20260815100636.861901-1-jinyu.tang@linux.dev> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260815095548.860018-1-jinyu.tang@linux.dev> References: <20260815095548.860018-1-jinyu.tang@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The generic KVM_PRE_FAULT_MEMORY ioctl lets userspace populate KVM page tables before running a vCPU over a GPA range. x86 already supports the ioctl, but RISC-V does not expose the capability and has no arch hook. Add the RISC-V arch hook and reuse the existing G-stage fault mapping path with a read access. Report progress using the G-stage mapping returned by the map path, so the ioctl can advance by the actual leaf size that covers the requested GPA. Retry until a mapping is installed or a signal, VM-dead request, or real error is observed. Signed-off-by: Jinyu Tang --- arch/riscv/kvm/Kconfig | 1 + arch/riscv/kvm/gstage.c | 3 +++ arch/riscv/kvm/mmu.c | 45 ++++++++++++++++++++++++++++++++++++++++- arch/riscv/kvm/vm.c | 1 + 4 files changed, 49 insertions(+), 1 deletion(-) diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig index ec2cee0a39e0..8ac209e8ac87 100644 --- a/arch/riscv/kvm/Kconfig +++ b/arch/riscv/kvm/Kconfig @@ -28,6 +28,7 @@ config KVM select KVM_COMMON select KVM_GENERIC_DIRTYLOG_READ_PROTECT select KVM_GENERIC_HARDWARE_ENABLING + select KVM_GENERIC_PRE_FAULT_MEMORY select KVM_MMIO select VIRT_XFER_TO_GUEST_WORK select SCHED_INFO diff --git a/arch/riscv/kvm/gstage.c b/arch/riscv/kvm/gstage.c index 54d45addf18f..dff315dfd24e 100644 --- a/arch/riscv/kvm/gstage.c +++ b/arch/riscv/kvm/gstage.c @@ -286,6 +286,9 @@ int kvm_riscv_gstage_map_page(struct kvm_gstage *gstage, out_map->level, true); } else if (ALIGN_DOWN(PFN_PHYS(pte_pfn(ptep_get(ptep))), page_size) == hpa) { kvm_riscv_gstage_update_pte_prot(gstage, ptep_level, gpa, ptep, prot); + out_map->addr = ALIGN_DOWN(gpa, page_size); + out_map->level = ptep_level; + out_map->pte = ptep_get(ptep); return 0; } } diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c index 2fabcd409991..f6ca86da53eb 100644 --- a/arch/riscv/kvm/mmu.c +++ b/arch/riscv/kvm/mmu.c @@ -717,7 +717,7 @@ int kvm_riscv_mmu_map(struct kvm_vcpu *vcpu, struct kvm_memory_slot *memslot, if (hfn == KVM_PFN_ERR_HWPOISON) { send_sig_mceerr(BUS_MCEERR_AR, (void __user *)hva, vma_pageshift, current); - return 0; + return -EFAULT; } if (is_error_noslot_pfn(hfn)) return -EFAULT; @@ -782,6 +782,49 @@ int kvm_riscv_mmu_map(struct kvm_vcpu *vcpu, struct kvm_memory_slot *memslot, return ret; } +long kvm_arch_vcpu_pre_fault_memory(struct kvm_vcpu *vcpu, + struct kvm_pre_fault_memory *range) +{ + struct kvm_gstage_mapping out_map = { 0 }; + struct kvm_memory_slot *memslot; + unsigned long map_size; + unsigned long hva; + gpa_t end; + gfn_t gfn; + int ret; + + gfn = gpa_to_gfn(range->gpa); + memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + if (!memslot) + return -ENOENT; + + hva = gfn_to_hva_memslot_prot(memslot, gfn, NULL); + if (kvm_is_error_hva(hva)) + return -ENOENT; + + for (;;) { + if (signal_pending(current)) + return -EINTR; + + if (kvm_check_request(KVM_REQ_VM_DEAD, vcpu)) + return -EIO; + + cond_resched(); + ret = kvm_riscv_mmu_map(vcpu, memslot, range->gpa, hva, false, &out_map); + if (ret) + return ret; + + if (!pte_val(out_map.pte)) + continue; + + map_size = PAGE_SIZE << (out_map.level * kvm_riscv_gstage_index_bits); + end = out_map.addr + map_size; + break; + } + + return min_t(u64, range->size, end - range->gpa); +} + int kvm_riscv_mmu_alloc_pgd(struct kvm *kvm) { struct page *pgd_page; diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c index a9f083feeb76..58500a19b33b 100644 --- a/arch/riscv/kvm/vm.c +++ b/arch/riscv/kvm/vm.c @@ -187,6 +187,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_MP_STATE: case KVM_CAP_IMMEDIATE_EXIT: case KVM_CAP_SET_GUEST_DEBUG: + case KVM_CAP_PRE_FAULT_MEMORY: r = 1; break; case KVM_CAP_NR_VCPUS: -- 2.43.0