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a=rsa-sha256; c=relaxed/simple; d=irrelevant.dk; s=default; t=1596030540; bh=Xmf7EAigExAi9sAZuX5NU9T71eGcb7yfbuJRQj5d+oE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bwecQQRc3LyglBoJYqqx/+/M4wGXc1p8W/+y13OdJJ/ymYGF19I4ZUt4dHac6pXoo pU5Q+pPmAzVsIjSLDAbu1tIBcQaEiveH9e6g4KHFB+RPIx6SMANzCUMLMmqXIgmGH5 oIX/gU+1hIFnLhy5Qb6hNTl+XaPF0zlxs98u+4fHIP8oNszyyJ6JTATBtc4iVhzj77 yWBw7MDnsXRKZJAt3EW9SPcCt1SxTThOcfriPm5bHzgZx7D5oE4o4vVIwZRztZ7UZu 0/pE2+QX3b/q50XuYHXnT2+eJek8aK1qHODqrf+bJwtPgPr5Dr0YvkEAPEf0l/usU7 liaiMXNqxFcaw== Date: Wed, 29 Jul 2020 15:48:56 +0200 From: Klaus Jensen To: Maxim Levitsky Subject: Re: [PATCH v3 12/18] hw/block/nvme: support the get/set features select and save fields Message-ID: <20200729134856.GA181110@apples.localdomain> References: <20200706061303.246057-1-its@irrelevant.dk> <20200706061303.246057-13-its@irrelevant.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=128.199.63.193; envelope-from=its@irrelevant.dk; helo=charlie.dont.surf X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/29 07:44:31 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-block@nongnu.org, Klaus Jensen , qemu-devel@nongnu.org, Max Reitz , Keith Busch , Javier Gonzalez , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Jul 29 16:17, Maxim Levitsky wrote: > On Mon, 2020-07-06 at 08:12 +0200, Klaus Jensen wrote: > > From: Klaus Jensen > > > > Since the device does not have any persistent state storage, no > > features are "saveable" and setting the Save (SV) field in any Set > > Features command will result in a Feature Identifier Not Saveable status > > code. > > > > Similarly, if the Select (SEL) field is set to request saved values, the > > devices will (as it should) return the default values instead. > > > > Since this also introduces "Supported Capabilities", the nsid field is > > now also checked for validity wrt. the feature being get/set'ed. > > > > Signed-off-by: Klaus Jensen > > --- > > hw/block/nvme.c | 103 +++++++++++++++++++++++++++++++++++++----- > > hw/block/trace-events | 4 +- > > include/block/nvme.h | 27 ++++++++++- > > 3 files changed, 119 insertions(+), 15 deletions(-) > > > > diff --git a/hw/block/nvme.c b/hw/block/nvme.c > > index 2d85e853403f..df8b786e4875 100644 > > --- a/hw/block/nvme.c > > +++ b/hw/block/nvme.c > > @@ -1083,20 +1091,47 @@ static uint16_t nvme_get_feature(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req) > > { > > uint32_t dw10 = le32_to_cpu(cmd->cdw10); > > uint32_t dw11 = le32_to_cpu(cmd->cdw11); > > + uint32_t nsid = le32_to_cpu(cmd->nsid); > > uint32_t result; > > uint8_t fid = NVME_GETSETFEAT_FID(dw10); > > + NvmeGetFeatureSelect sel = NVME_GETFEAT_SELECT(dw10); > > uint16_t iv; > > > > static const uint32_t nvme_feature_default[NVME_FID_MAX] = { > > [NVME_ARBITRATION] = NVME_ARB_AB_NOLIMIT, > > }; > > > > - trace_pci_nvme_getfeat(nvme_cid(req), fid, dw11); > > + trace_pci_nvme_getfeat(nvme_cid(req), fid, sel, dw11); > > > > if (!nvme_feature_support[fid]) { > > return NVME_INVALID_FIELD | NVME_DNR; > > } > > > > + if (nvme_feature_cap[fid] & NVME_FEAT_CAP_NS) { > > + if (!nsid || nsid > n->num_namespaces) { > > + /* > > + * The Reservation Notification Mask and Reservation Persistence > > + * features require a status code of Invalid Field in Command when > > + * NSID is 0xFFFFFFFF. Since the device does not support those > > + * features we can always return Invalid Namespace or Format as we > > + * should do for all other features. > > + */ > > + return NVME_INVALID_NSID | NVME_DNR; > > + } > > + } > > + > > + switch (sel) { > > + case NVME_GETFEAT_SELECT_CURRENT: > > + break; > > + case NVME_GETFEAT_SELECT_SAVED: > > + /* no features are saveable by the controller; fallthrough */ > > + case NVME_GETFEAT_SELECT_DEFAULT: > > + goto defaults; > > I hate to say it, but while I have nothing against using 'goto' (unlike some types I met), > In this particular case it feels like it would be better to have a separate function for > defaults, or have even have a a separate function per feature and have it return current/default/saved/whatever > value. The later would allow to have each feature self contained in its own function. > > But on the other hand I see that you fail back to defaults for unchangeble features, which does make > sense. In other words, I don't have strong opinion against using goto here after all. > > When feature code will be getting more features in the future (pun intended) you probably will have to split it,\ > like I suggest to keep code complexity low. > Argh... I know you are right. Since you are "accepting" the current state with your R-b and it already carries one from Dmitry I think I'll let this stay for now, but I will fix this in a follow up patch for sure. > > @@ -926,6 +949,8 @@ typedef struct NvmeLBAF { > > uint8_t rp; > > } NvmeLBAF; > > > > +#define NVME_NSID_BROADCAST 0xffffffff > > Cool, you probably want eventually to go over code and > change all places that use the number to the define. > (No need to do this now) > True. Noted :)