On Wed, 23 Oct 2019 09:53:04 +0800 Lu Baolu <baolu...@linux.intel.com> wrote:
> Hi Ashok, > > Thanks for reviewing the patch. > > On 10/23/19 8:45 AM, Raj, Ashok wrote: > > On Tue, Oct 22, 2019 at 04:53:14PM -0700, Jacob Pan wrote: > >> From: Lu Baolu <baolu...@linux.intel.com> > >> > >> If Intel IOMMU runs in caching mode, a.k.a. virtual IOMMU, the > >> IOMMU driver should rely on the emulation software to allocate > >> and free PASID IDs. The Intel vt-d spec revision 3.0 defines a > >> register set to support this. This includes a capability register, > >> a virtual command register and a virtual response register. Refer > >> to section 10.4.42, 10.4.43, 10.4.44 for more information. > > > > The above paragraph seems a bit confusing, there is no reference > > to caching mode for for VCMD... some suggestion below. > > > > Enabling IOMMU in a guest requires communication with the host > > driver for certain aspects. Use of PASID ID to enable Shared Virtual > > Addressing (SVA) requires managing PASID's in the host. VT-d 3.0 > > spec provides a Virtual Command Register (VCMD) to facilitate this. > > Writes to this register in the guest are trapped by Qemu and > > proxies the call to the host driver.... > > Yours is better. Will use it. > I will roll that in to v7 > > > > > >> > >> This patch adds the enlightened PASID allocation/free interfaces > >> via the virtual command register. > >> > >> Cc: Ashok Raj <ashok....@intel.com> > >> Cc: Jacob Pan <jacob.jun....@linux.intel.com> > >> Cc: Kevin Tian <kevin.t...@intel.com> > >> Signed-off-by: Liu Yi L <yi.l....@intel.com> > >> Signed-off-by: Lu Baolu <baolu...@linux.intel.com> > >> Signed-off-by: Jacob Pan <jacob.jun....@linux.intel.com> > >> Reviewed-by: Eric Auger <eric.au...@redhat.com> > >> --- > >> drivers/iommu/intel-pasid.c | 83 > >> +++++++++++++++++++++++++++++++++++++++++++++ > >> drivers/iommu/intel-pasid.h | 13 ++++++- > >> include/linux/intel-iommu.h | 2 ++ 3 files changed, 97 > >> insertions(+), 1 deletion(-) > >> > >> diff --git a/drivers/iommu/intel-pasid.c > >> b/drivers/iommu/intel-pasid.c index 040a445be300..76bcbb21e112 > >> 100644 --- a/drivers/iommu/intel-pasid.c > >> +++ b/drivers/iommu/intel-pasid.c > >> @@ -63,6 +63,89 @@ void *intel_pasid_lookup_id(int pasid) > >> return p; > >> } > >> > >> +static int check_vcmd_pasid(struct intel_iommu *iommu) > >> +{ > >> + u64 cap; > >> + > >> + if (!ecap_vcs(iommu->ecap)) { > >> + pr_warn("IOMMU: %s: Hardware doesn't support > >> virtual command\n", > >> + iommu->name); > >> + return -ENODEV; > >> + } > >> + > >> + cap = dmar_readq(iommu->reg + DMAR_VCCAP_REG); > >> + if (!(cap & DMA_VCS_PAS)) { > >> + pr_warn("IOMMU: %s: Emulation software doesn't > >> support PASID allocation\n", > >> + iommu->name); > >> + return -ENODEV; > >> + } > >> + > >> + return 0; > >> +} > >> + > >> +int vcmd_alloc_pasid(struct intel_iommu *iommu, unsigned int > >> *pasid) +{ > >> + u64 res; > >> + u8 status_code; > >> + unsigned long flags; > >> + int ret = 0; > >> + > >> + ret = check_vcmd_pasid(iommu); > > > > Do you have to check this everytime? every dmar_readq is going to > > trap to the other side ... > > Yes. We don't need to check it every time. Check once and save the > result during boot is enough. > > How about below incremental change? > Below is good but I was thinking to include vccap in struct intel_iommu{} where cap and ecaps reside. i.e. diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h index 14b87ae2916a..e2cf25c9c956 100644 --- a/include/linux/intel-iommu.h +++ b/include/linux/intel-iommu.h @@ -528,6 +528,7 @@ struct intel_iommu { u64 reg_size; /* size of hw register set */ u64 cap; u64 ecap; + u64 vccap; Also, we can use a static branch here. > diff --git a/drivers/iommu/intel-pasid.c b/drivers/iommu/intel-pasid.c > index ff7e877b7a4d..c15d9d7e1e73 100644 > --- a/drivers/iommu/intel-pasid.c > +++ b/drivers/iommu/intel-pasid.c > @@ -29,22 +29,29 @@ u32 intel_pasid_max_id = PASID_MAX; > > static int check_vcmd_pasid(struct intel_iommu *iommu) > { > + static int vcmd_supported = -EINVAL; > u64 cap; > > + if (vcmd_supported != -EINVAL) > + return vcmd_supported; > + > if (!ecap_vcs(iommu->ecap)) { > pr_warn("IOMMU: %s: Hardware doesn't support virtual > command\n", > iommu->name); > - return -ENODEV; > + vcmd_supported = -ENODEV; > + return vcmd_supported; > } > > cap = dmar_readq(iommu->reg + DMAR_VCCAP_REG); > if (!(cap & DMA_VCS_PAS)) { > pr_warn("IOMMU: %s: Emulation software doesn't > support PASID allocation\n", > iommu->name); > - return -ENODEV; > + vcmd_supported = -ENODEV; > + return vcmd_supported; > } > > - return 0; > + vcmd_supported = 0; > + return vcmd_supported; > } > > int vcmd_alloc_pasid(struct intel_iommu *iommu, unsigned int *pasid) > > Best regards, > baolu > > > > >> + if (ret) > >> + return ret; > >> + > >> + raw_spin_lock_irqsave(&iommu->register_lock, flags); > >> + dmar_writeq(iommu->reg + DMAR_VCMD_REG, VCMD_CMD_ALLOC); > >> + IOMMU_WAIT_OP(iommu, DMAR_VCRSP_REG, dmar_readq, > >> + !(res & VCMD_VRSP_IP), res); > >> + raw_spin_unlock_irqrestore(&iommu->register_lock, flags); > >> + > >> + status_code = VCMD_VRSP_SC(res); > >> + switch (status_code) { > >> + case VCMD_VRSP_SC_SUCCESS: > >> + *pasid = VCMD_VRSP_RESULT(res); > >> + break; > >> + case VCMD_VRSP_SC_NO_PASID_AVAIL: > >> + pr_info("IOMMU: %s: No PASID available\n", > >> iommu->name); > >> + ret = -ENOMEM; > >> + break; > >> + default: > >> + ret = -ENODEV; > >> + pr_warn("IOMMU: %s: Unexpected error code %d\n", > >> + iommu->name, status_code); > >> + } > >> + > >> + return ret; > >> +} > >> + > >> +void vcmd_free_pasid(struct intel_iommu *iommu, unsigned int > >> pasid) +{ > >> + u64 res; > >> + u8 status_code; > >> + unsigned long flags; > >> + > >> + if (check_vcmd_pasid(iommu)) > >> + return; > >> + > >> + raw_spin_lock_irqsave(&iommu->register_lock, flags); > >> + dmar_writeq(iommu->reg + DMAR_VCMD_REG, (pasid << 8) | > >> VCMD_CMD_FREE); > >> + IOMMU_WAIT_OP(iommu, DMAR_VCRSP_REG, dmar_readq, > >> + !(res & VCMD_VRSP_IP), res); > >> + raw_spin_unlock_irqrestore(&iommu->register_lock, flags); > >> + > >> + status_code = VCMD_VRSP_SC(res); > >> + switch (status_code) { > >> + case VCMD_VRSP_SC_SUCCESS: > >> + break; > >> + case VCMD_VRSP_SC_INVALID_PASID: > >> + pr_info("IOMMU: %s: Invalid PASID\n", > >> iommu->name); > >> + break; > >> + default: > >> + pr_warn("IOMMU: %s: Unexpected error code %d\n", > >> + iommu->name, status_code); > >> + } > >> +} > >> + > >> /* > >> * Per device pasid table management: > >> */ > >> diff --git a/drivers/iommu/intel-pasid.h > >> b/drivers/iommu/intel-pasid.h index fc8cd8f17de1..e413e884e685 > >> 100644 --- a/drivers/iommu/intel-pasid.h > >> +++ b/drivers/iommu/intel-pasid.h > >> @@ -23,6 +23,16 @@ > >> #define is_pasid_enabled(entry) (((entry)->lo >> > >> 3) & 0x1) #define get_pasid_dir_size(entry) (1 << > >> ((((entry)->lo >> 9) & 0x7) + 7)) > >> +/* Virtual command interface for enlightened pasid management. */ > >> +#define VCMD_CMD_ALLOC 0x1 > >> +#define VCMD_CMD_FREE 0x2 > >> +#define VCMD_VRSP_IP 0x1 > >> +#define VCMD_VRSP_SC(e) (((e) >> 1) & 0x3) > >> +#define VCMD_VRSP_SC_SUCCESS 0 > >> +#define VCMD_VRSP_SC_NO_PASID_AVAIL 1 > >> +#define VCMD_VRSP_SC_INVALID_PASID 1 > >> +#define VCMD_VRSP_RESULT(e) (((e) >> 8) & 0xfffff) > >> + > >> /* > >> * Domain ID reserved for pasid entries programmed for > >> first-level > >> * only and pass-through transfer modes. > >> @@ -95,5 +105,6 @@ int intel_pasid_setup_pass_through(struct > >> intel_iommu *iommu, struct device *dev, int pasid); > >> void intel_pasid_tear_down_entry(struct intel_iommu *iommu, > >> struct device *dev, int pasid); > >> - > >> +int vcmd_alloc_pasid(struct intel_iommu *iommu, unsigned int > >> *pasid); +void vcmd_free_pasid(struct intel_iommu *iommu, unsigned > >> int pasid); #endif /* __INTEL_PASID_H */ > >> diff --git a/include/linux/intel-iommu.h > >> b/include/linux/intel-iommu.h index ed11ef594378..eea7468694a7 > >> 100644 --- a/include/linux/intel-iommu.h > >> +++ b/include/linux/intel-iommu.h > >> @@ -161,6 +161,7 @@ > >> #define ecap_smpwc(e) (((e) >> 48) & 0x1) > >> #define ecap_flts(e) (((e) >> 47) & 0x1) > >> #define ecap_slts(e) (((e) >> 46) & 0x1) > >> +#define ecap_vcs(e) (((e) >> 44) & 0x1) > >> #define ecap_smts(e) (((e) >> 43) & 0x1) > >> #define ecap_dit(e) ((e >> 41) & 0x1) > >> #define ecap_pasid(e) ((e >> 40) & 0x1) > >> @@ -279,6 +280,7 @@ > >> > >> /* PRS_REG */ > >> #define DMA_PRS_PPR ((u32)1) > >> +#define DMA_VCS_PAS ((u64)1) > >> > >> #define IOMMU_WAIT_OP(iommu, offset, op, cond, > >> sts) \ do > >> { > >> \ -- 2.7.4 > >> > > [Jacob Pan]