From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7D60B42E013; Thu, 30 Apr 2026 14:43:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777560189; cv=none; b=ZiMrqcnEmVO5vdD0MLgaqIcWJTbfrKNcMJgiyGtAHfLfnjlpfPZc+XRD51JcqyY61PAa3htbGDDmHXsVBiHHuwv6xSEou/aYcBcOCuYBoDtEKkTE1K2dqgGozXzgMrE8magdQSz17IDPwnaO3OTkbkccu0golKpv8NXDJBVpkuQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777560189; c=relaxed/simple; bh=TgQ+8B0EQItchvW3mww44hNv34hBdvXfyuGMdfZPV1E=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=qPdKvFI5O6Q/3CqmSAESbBnaKqepTh5IftE42m/g3898ZLG4xB1NuVvGU7BybJol5I5veYSNjrcoaGICzwySb48ukS5dMtQI3aQ6WRIZdhVwZaCzxiky5n3/smABv3LB3ngK9flSXrrHJt5+4cGkFZBRwGrW1S6cDd5z2D+qWGI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=Iv84x6cp; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="Iv84x6cp" Received: from skinsburskii.localdomain (unknown [40.65.108.177]) by linux.microsoft.com (Postfix) with ESMTPSA id 3BFA020B7175; Thu, 30 Apr 2026 07:43:07 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 3BFA020B7175 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1777560187; bh=sRa5PAsDpja/M7JrLAVV6AOmTtwR2FeCnccsrJc5s2Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Iv84x6cpaQigON5OukTX4vt/5pDuLJ8CCC5U5gLK0XNgOyaeYCTC00QEb3tLjbh6i 1I5lFFhJ7VWmYrXMfhMNDLQwzYXssXs8iF1N8ulERi1juEg/VyjtgqCq1++8/bTsVt +1z5lXYtZs4X0ED+sezumh1NQCDgApzND61gb7NI= Date: Thu, 30 Apr 2026 07:43:05 -0700 From: Stanislav Kinsburskii To: Mukesh R Cc: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, longli@microsoft.com, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mshv: Simplify GPA map/unmap hypercall helpers Message-ID: References: <177748126383.33250.14844440376241852870.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net> <61e5d806-b5d5-ab2c-0e09-6def449d5582@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <61e5d806-b5d5-ab2c-0e09-6def449d5582@linux.microsoft.com> On Wed, Apr 29, 2026 at 07:06:08PM -0700, Mukesh R wrote: > > On 4/29/26 09:48, Stanislav Kinsburskii wrote: > > Clean up hv_do_map_gpa_hcall() and hv_call_unmap_gpa_pages() after the > > preceding bug-fix patches: > > > > Move "done += completed" before the status checks so that pages mapped > > by a partially-successful batch are included in the error cleanup unmap. > > Previously these mappings were leaked on failure. > > > > While here, improve type safety and readability: > > - Change "int done" to "u64 done" to match the u64 page_count it is > > compared against, avoiding signed/unsigned comparison hazards. > > - Use u64 for loop iteration and batch size variables consistently. > > - Add proper braces to the for-loop body in hv_do_map_gpa_hcall(). > > - Remove unnecessary "ret" variable from hv_call_unmap_gpa_pages(). > > - Simplify the error-path unmap to use "done << large_shift" directly > > instead of mutating done in place. > > > > what changed in V2? > No functional changes: "min" was replaced with "min_t" (reported by checkpatch.pl). > > Fixes: 621191d709b14 ("Drivers: hv: Introduce mshv_root module to expose /dev/mshv to VMMs") > > Signed-off-by: Stanislav Kinsburskii > > --- > > drivers/hv/mshv_root_hv_call.c | 55 +++++++++++++++------------------------- > > 1 file changed, 20 insertions(+), 35 deletions(-) > > > > diff --git a/drivers/hv/mshv_root_hv_call.c b/drivers/hv/mshv_root_hv_call.c > > index e5992c324904a..1f19a4ca824f0 100644 > > --- a/drivers/hv/mshv_root_hv_call.c > > +++ b/drivers/hv/mshv_root_hv_call.c > > @@ -195,8 +195,8 @@ static int hv_do_map_gpa_hcall(u64 partition_id, u64 gfn, u64 page_struct_count, > > struct hv_input_map_gpa_pages *input_page; > > u64 status, *pfnlist; > > unsigned long irq_flags, large_shift = 0; > > - int ret = 0, done = 0; > > - u64 page_count = page_struct_count; > > + u64 done = 0, page_count = page_struct_count; > > + int ret = 0; > > if (page_count == 0 || (pages && mmio_spa)) > > return -EINVAL; > > @@ -213,8 +213,8 @@ static int hv_do_map_gpa_hcall(u64 partition_id, u64 gfn, u64 page_struct_count, > > } > > while (done < page_count) { > > - ulong i, completed, remain = page_count - done; > > - int rep_count = min(remain, HV_MAP_GPA_BATCH_SIZE); > > + u64 i, completed, remain = page_count - done; > > + u64 rep_count = min_t(u64, remain, HV_MAP_GPA_BATCH_SIZE); > > local_irq_save(irq_flags); > > input_page = *this_cpu_ptr(hyperv_pcpu_input_arg); > > @@ -224,23 +224,13 @@ static int hv_do_map_gpa_hcall(u64 partition_id, u64 gfn, u64 page_struct_count, > > input_page->map_flags = flags; > > pfnlist = input_page->source_gpa_page_list; > > - for (i = 0; i < rep_count; i++) > > - if (flags & HV_MAP_GPA_NO_ACCESS) { > > + for (i = 0; i < rep_count; i++) { > > + if (flags & HV_MAP_GPA_NO_ACCESS) > > pfnlist[i] = 0; > > - } else if (pages) { > > - u64 index = (done + i) << large_shift; > > - > > - if (index >= page_struct_count) { > > - ret = -EINVAL; > > - break; > > - } > > - pfnlist[i] = page_to_pfn(pages[index]); > > - } else { > > + else if (pages) > > + pfnlist[i] = page_to_pfn(pages[(done + i) << large_shift]); > > Entire file is 80 cols, please don't cause this one overflow. > Sure. I'll update. Thanks, Stanislav > Thanks, > -Mukesh > > > > + else > > pfnlist[i] = mmio_spa + done + i; > > - } > > - if (ret) { > > - local_irq_restore(irq_flags); > > - break; > > } > > status = hv_do_rep_hypercall(HVCALL_MAP_GPA_PAGES, rep_count, 0, > > @@ -248,29 +238,26 @@ static int hv_do_map_gpa_hcall(u64 partition_id, u64 gfn, u64 page_struct_count, > > local_irq_restore(irq_flags); > > completed = hv_repcomp(status); > > + done += completed; > > if (hv_result_needs_memory(status)) { > > ret = hv_call_deposit_pages(NUMA_NO_NODE, partition_id, > > HV_MAP_GPA_DEPOSIT_PAGES); > > if (ret) > > break; > > - > > } else if (!hv_result_success(status)) { > > ret = hv_result_to_errno(status); > > break; > > } > > - > > - done += completed; > > } > > if (ret && done) { > > u32 unmap_flags = 0; > > - if (flags & HV_MAP_GPA_LARGE_PAGE) { > > + if (flags & HV_MAP_GPA_LARGE_PAGE) > > unmap_flags |= HV_UNMAP_GPA_LARGE_PAGE; > > - done <<= large_shift; > > - } > > - hv_call_unmap_gpa_pages(partition_id, gfn, done, unmap_flags); > > + hv_call_unmap_gpa_pages(partition_id, gfn, > > + done << large_shift, unmap_flags); > > } > > return ret; > > @@ -305,7 +292,7 @@ int hv_call_unmap_gpa_pages(u64 partition_id, u64 gfn, u64 page_count_4k, > > struct hv_input_unmap_gpa_pages *input_page; > > u64 status, page_count = page_count_4k; > > unsigned long irq_flags, large_shift = 0; > > - int ret = 0, done = 0; > > + u64 done = 0; > > if (page_count == 0) > > return -EINVAL; > > @@ -319,8 +306,8 @@ int hv_call_unmap_gpa_pages(u64 partition_id, u64 gfn, u64 page_count_4k, > > } > > while (done < page_count) { > > - ulong completed, remain = page_count - done; > > - int rep_count = min(remain, HV_UMAP_GPA_PAGES); > > + u64 completed, remain = page_count - done; > > + u64 rep_count = min_t(u64, remain, HV_UMAP_GPA_PAGES); > > local_irq_save(irq_flags); > > input_page = *this_cpu_ptr(hyperv_pcpu_input_arg); > > @@ -333,15 +320,13 @@ int hv_call_unmap_gpa_pages(u64 partition_id, u64 gfn, u64 page_count_4k, > > local_irq_restore(irq_flags); > > completed = hv_repcomp(status); > > - if (!hv_result_success(status)) { > > - ret = hv_result_to_errno(status); > > - break; > > - } > > - > > done += completed; > > + > > + if (!hv_result_success(status)) > > + return hv_result_to_errno(status); > > } > > - return ret; > > + return 0; > > } > > int hv_call_get_gpa_access_states(u64 partition_id, u32 count, u64 gpa_base_pfn, > > > > >