From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Chen, Tiejun" Subject: Re: [v2][PATCH 2/2] libxl: introduce gfx_passthru_kind Date: Fri, 20 Mar 2015 09:04:07 +0800 Message-ID: <550B7207.6020503__42590.4673211791$1426813568$gmane$org@intel.com> References: <1425980538-5508-1-git-send-email-tiejun.chen@intel.com> <1425980538-5508-3-git-send-email-tiejun.chen@intel.com> <1426073641.21353.192.camel@citrix.com> <55010596.2030106@intel.com> <1426163186.21353.409.camel@citrix.com> <55023FDA.7030204@intel.com> <1426241479.32572.94.camel@citrix.com> <55062CD2.8050305@intel.com> <1426508400.18247.33.camel@citrix.com> <5507DBD6.8030401@intel.com> <1426584396.18247.136.camel@citrix.com> <55092A24.8010409@intel.com> <1426674310.18247.318.camel@citrix.com> <550A2F6A.4060508@intel.com> <1426761860.610.22.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1426761860.610.22.camel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: Ian.Jackson@eu.citrix.com, wei.liu2@citrix.com, qemu-devel@nongnu.org, stefano.stabellini@citrix.com, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 2015/3/19 18:44, Ian Campbell wrote: > On Thu, 2015-03-19 at 10:07 +0800, Chen, Tiejun wrote: >>> This duplicates the code from above. I think this would be best done as: >>> >>> static int libxl__detect_gfx_passthru_kind(libxl__gc *gc, guest_config) >>> { >>> if (b_info->u.hvm.gfx_passthru_kind != LIBXL_GFX_PASSTHRU_KIND_DEFAULT) >>> return 0; >>> >>> if (libxl__is_igd_vga_passthru(gc, guest_config)) { >>> b_info->u.hvm.gfx_passthru_kind = LIBXL_GFX_PASSTHRU_KIND_IGD; >>> return 0; >>> } >>> >>> LOG(ERROR, "Unable to detect graphics passthru kind"); >>> return 1; >>> } >>> >>> Then for the code in libxl__build_device_model_args_new: >>> >>> if (libxl_defbool_val(b_info->u.hvm.gfx_passthru)) { >>> if (!libxl__detect_gfx_passthru_kind(gc, guest_config)) >>> return NULL >>> switch (b_info->u.hvm.gfx_passthru_kind) { >>> case LIBXL_GFX_PASSTHRU_KIND_IGD: >>> machinearg = GCSPRINTF("%s,igd-passthru=on", machinearg); >>> break; >>> default: >>> LOG(ERROR, "unknown gfx_passthru_kind\n"); >>> return NULL; >>> } >>> } >>> >>> That is, a helper to try and autodetect kind if it is default and then a >>> single switch entry for each kind. >>> >>>> + default: >>>> + LOG(WARN, "gfx_passthru_kind is invalid so ignored.\n"); >>> >>> Please return an error here, as I've shown above. >> >> Looks good and thanks, but here 'guest_config' is a const so we >> shouldn't/can't reset b_info->u.hvm.gfx_passthru_kind like this, >> >> b_info->u.hvm.gfx_passthru_kind = LIBXL_GFX_PASSTHRU_KIND_IGD; >> >> So I tried to refactor a little bit to follow up yours, >> >> diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c >> index 8599a6a..605b17c 100644 >> --- a/tools/libxl/libxl_dm.c >> +++ b/tools/libxl/libxl_dm.c >> @@ -409,6 +409,23 @@ static char *dm_spice_options(libxl__gc *gc, >> return opt; >> } >> >> +static int >> +libxl__detect_gfx_passthru_kind(libxl__gc *gc, >> + const libxl_domain_config *guest_config) >> +{ >> + const libxl_domain_build_info *b_info = &guest_config->b_info; >> + >> + if (b_info->u.hvm.gfx_passthru_kind != LIBXL_GFX_PASSTHRU_KIND_DEFAULT) >> + return b_info->u.hvm.gfx_passthru_kind; >> + >> + if (libxl__is_igd_vga_passthru(gc, guest_config)) { >> + return LIBXL_GFX_PASSTHRU_KIND_IGD; >> + } >> + >> + LOG(ERROR, "Unable to detect graphics passthru kind"); >> + return -1; > > I think you can make this function return enum > libxl_gfx_passthrough_kind and then return > LIBXL_GFX_PASSTHRU_KIND_DEFAULT in this case. > >> +} >> + >> static char ** libxl__build_device_model_args_new(libxl__gc *gc, >> const char *dm, int guest_domid, >> const libxl_domain_config >> *guest_config, >> @@ -427,7 +444,7 @@ static char ** >> libxl__build_device_model_args_new(libxl__gc *gc, >> const char *keymap = dm_keymap(guest_config); >> char *machinearg; >> flexarray_t *dm_args; >> - int i, connection, devid; >> + int i, connection, devid, gfx_passthru_kind; > > Please declare this in the smallest necessary scope... > [...] >> + if (libxl_defbool_val(b_info->u.hvm.gfx_passthru)) { >> + gfx_passthru_kind = libxl__detect_gfx_passthru_kind(gc, > > i.e. here. > >> + >> guest_config); >> + switch (gfx_passthru_kind) { >> + case LIBXL_GFX_PASSTHRU_KIND_IGD: >> + machinearg = GCSPRINTF("%s,igd-passthru=on", machinearg); >> + break; >> + default: > > With the suggestion to return KIND_DEFAULT if detection fails then I > think an extra case should be added: > case LIBXL_GFX_PASSTHRU_KIND_DEFAULT: > LOG(ERROR, "unable to detect required > gfx_passthru_kind"); > return NULL; > >> + LOG(ERROR, "unknown gfx_passthru_kind\n"); > > I think LOG is supposed to not include the final \n. > Refactor again, diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c index 8599a6a..05c8916 100644 --- a/tools/libxl/libxl_dm.c +++ b/tools/libxl/libxl_dm.c @@ -409,6 +409,23 @@ static char *dm_spice_options(libxl__gc *gc, return opt; } +static enum libxl_gfx_passthru_kind +libxl__detect_gfx_passthru_kind(libxl__gc *gc, + const libxl_domain_config *guest_config) +{ + const libxl_domain_build_info *b_info = &guest_config->b_info; + + if (b_info->u.hvm.gfx_passthru_kind != LIBXL_GFX_PASSTHRU_KIND_DEFAULT) + return b_info->u.hvm.gfx_passthru_kind; + + if (libxl__is_igd_vga_passthru(gc, guest_config)) { + return LIBXL_GFX_PASSTHRU_KIND_IGD; + } + + LOG(ERROR, "Unable to detect graphics passthru kind"); + return LIBXL_GFX_PASSTHRU_KIND_DEFAULT; +} + static char ** libxl__build_device_model_args_new(libxl__gc *gc, const char *dm, int guest_domid, const libxl_domain_config *guest_config, @@ -757,6 +771,21 @@ static char ** libxl__build_device_model_args_new(libxl__gc *gc, machinearg, max_ram_below_4g); } } + + if (libxl_defbool_val(b_info->u.hvm.gfx_passthru)) { + enum libxl_gfx_passthru_kind gfx_passthru_kind = + libxl__detect_gfx_passthru_kind(gc, guest_config); + switch (gfx_passthru_kind) { + case LIBXL_GFX_PASSTHRU_KIND_IGD: + machinearg = GCSPRINTF("%s,igd-passthru=on", machinearg); + break; + case LIBXL_GFX_PASSTHRU_KIND_DEFAULT: + LOG(ERROR, "unable to detect required gfx_passthru_kind"); + default: + return NULL; + } + } + flexarray_append(dm_args, machinearg); for (i = 0; b_info->extra_hvm && b_info->extra_hvm[i] != NULL; i++) flexarray_append(dm_args, b_info->extra_hvm[i]); Thanks Tiejun