| Message ID | 20241024090629.1944820-1-Jiqian.Chen@amd.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [QEMU,v9] xen/passthrough: use gsi to map pirq when dom0 is PVH | expand |
Hi, On 2024/10/24 17:06, Jiqian Chen wrote: > In PVH dom0, when passthrough a device to domU, QEMU code > xen_pt_realize->xc_physdev_map_pirq wants to use gsi, but in current codes > the gsi number is got from file /sys/bus/pci/devices/<sbdf>/irq, that is > wrong, because irq is not equal with gsi, they are in different spaces, so > pirq mapping fails. > > To solve above problem, use new interface of Xen, xc_pcidev_get_gsi to get > gsi and use xc_physdev_map_pirq_gsi to map pirq when dom0 is PVH. > > Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com> > Signed-off-by: Huang Rui <ray.huang@amd.com> > Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com> > --- > Hi All, > This is v9 to support passthrough on Xen when dom0 is PVH. > v8->v9 changes: > * Moved the definition of PCI_SBDF from /hw/xen/xen_pt.c to /include/hw/pci/pci.h. > * Renamed xen_run_qemu_on_hvm to xen_pt_need_gsi. > * Renamed xen_map_pirq_for_gsi to xen_pt_map_pirq_for_gsi. > * Through reading /sys/hypervisor/guest_type to get dom type instead of using xc_domain_getinfo_single. > > Best regards, > Jiqian Chen > > v7->v8 changes: > * Since xc_physdev_gsi_from_dev was renamed to xc_pcidev_get_gsi, changed it. > * Added xen_run_qemu_on_hvm to check if Qemu run on PV dom0, if not use xc_physdev_map_pirq_gsi to map pirq. > * Used CONFIG_XEN_CTRL_INTERFACE_VERSION to wrap the new part for compatibility. > * Added "#define DOMID_RUN_QEMU 0" to represent the id of domain that Qemu run on. > > v6->v7 changes: > * Because the function of obtaining gsi was changed on the kernel and Xen side. Changed to use > xc_physdev_gsi_from_dev, that requires passing in sbdf instead of irq. > > v5->v6 changes: > * Because the function of obtaining gsi was changed on the kernel and Xen side. Changed to use > xc_physdev_gsi_from_irq, instead of gsi sysfs. > * Since function changed, removed the Review-by of Stefano. > > v4->v5 changes: > * Added Review-by Stefano. > > v3->v4 changes: > * Added gsi into struct XenHostPCIDevice and used gsi number that read from gsi sysfs > if it exists, if there is no gsi sysfs, still use irq. > > v2->v3 changes: > * Due to changes in the implementation of the second patch on kernel side(that adds > a new sysfs for gsi instead of a new syscall), so read gsi number from the sysfs of gsi. > > v1 and v2: > We can record the relation between gsi and irq, then when userspace(qemu) want > to use gsi, we can do a translation. The third patch of kernel(xen/privcmd: Add new syscall > to get gsi from irq) records all the relations in acpi_register_gsi_xen_pvh() when dom0 > initialize pci devices, and provide a syscall for userspace to get the gsi from irq. The > third patch of xen(tools: Add new function to get gsi from irq) add a new function > xc_physdev_gsi_from_irq() to call the new syscall added on kernel side. > And then userspace can use that function to get gsi. Then xc_physdev_map_pirq() will success. > > Issues we encountered: > 1. failed to map pirq for gsi > Problem: qemu will call xc_physdev_map_pirq() to map a passthrough device's gsi to pirq in > function xen_pt_realize(). But failed. > > Reason: According to the implement of xc_physdev_map_pirq(), it needs gsi instead of irq, > but qemu pass irq to it and treat irq as gsi, it is got from file > /sys/bus/pci/devices/xxxx:xx:xx.x/irq in function xen_host_pci_device_get(). But actually > the gsi number is not equal with irq. They are in different space. > --- > hw/xen/xen_pt.c | 53 ++++++++++++++++++++++++++++++++++++++++++++ > include/hw/pci/pci.h | 4 ++++ > 2 files changed, 57 insertions(+) > > diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c > index 3635d1b39f79..5b10d501d566 100644 > --- a/hw/xen/xen_pt.c > +++ b/hw/xen/xen_pt.c > @@ -766,6 +766,50 @@ static void xen_pt_destroy(PCIDevice *d) { > } > /* init */ > > +#if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 42000 > +static bool xen_pt_need_gsi(void) > +{ > + FILE *fp; > + int len; > + char type[10]; > + const char *guest_type = "/sys/hypervisor/guest_type"; > + > + fp = fopen(guest_type, "r"); > + if (fp == NULL) { > + error_report("Cannot open %s: %s", guest_type, strerror(errno)); > + return false; > + } > + fgets(type, sizeof(type), fp); > + fclose(fp); > + > + len = strlen(type); > + if (len) { > + type[len - 1] = '\0'; > + if (!strcmp(type, "PVH")) { > + return true; > + } > + } > + return false; > +} > + > +static int xen_pt_map_pirq_for_gsi(PCIDevice *d, int *pirq) > +{ > + int gsi; > + XenPCIPassthroughState *s = XEN_PT_DEVICE(d); > + > + gsi = xc_pcidev_get_gsi(xen_xc, > + PCI_SBDF(s->real_device.domain, > + s->real_device.bus, > + s->real_device.dev, > + s->real_device.func)); > + if (gsi >= 0) { > + return xc_physdev_map_pirq_gsi(xen_xc, xen_domid, gsi, pirq); > + } > + > + return gsi; > +} > +#endif > + > static void xen_pt_realize(PCIDevice *d, Error **errp) > { > ERRP_GUARD(); > @@ -847,7 +891,16 @@ static void xen_pt_realize(PCIDevice *d, Error **errp) > goto out; > } > > +#if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 42000 > + if (xen_pt_need_gsi()) { > + rc = xen_pt_map_pirq_for_gsi(d, &pirq); > + } else { > + rc = xc_physdev_map_pirq(xen_xc, xen_domid, machine_irq, &pirq); > + } > +#else > rc = xc_physdev_map_pirq(xen_xc, xen_domid, machine_irq, &pirq); > +#endif > + > if (rc < 0) { > XEN_PT_ERR(d, "Mapping machine irq %u to pirq %i failed, (err: %d)\n", > machine_irq, pirq, errno); > diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h > index eb26cac81098..07805aa8a5f3 100644 > --- a/include/hw/pci/pci.h > +++ b/include/hw/pci/pci.h > @@ -23,6 +23,10 @@ extern bool pci_available; > #define PCI_SLOT_MAX 32 > #define PCI_FUNC_MAX 8 > > +#define PCI_SBDF(seg, bus, dev, func) \ > + ((((uint32_t)(seg)) << 16) | \ > + (PCI_BUILD_BDF(bus, PCI_DEVFN(dev, func)))) > + > /* Class, Vendor and Device IDs from Linux's pci_ids.h */ > #include "hw/pci/pci_ids.h" > Do you have any comments?
On 10/24/24 05:06, Jiqian Chen wrote: > diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c > index 3635d1b39f79..5b10d501d566 100644 > --- a/hw/xen/xen_pt.c > +++ b/hw/xen/xen_pt.c > @@ -766,6 +766,50 @@ static void xen_pt_destroy(PCIDevice *d) { > } > /* init */ > > +#if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 42000 > +static bool xen_pt_need_gsi(void) > +{ > + FILE *fp; > + int len; > + char type[10]; A brief in-code comment to explain how you arrived at 10 would be appreciated. > + const char *guest_type = "/sys/hypervisor/guest_type"; > + > + fp = fopen(guest_type, "r"); > + if (fp == NULL) { > + error_report("Cannot open %s: %s", guest_type, strerror(errno)); > + return false; > + } > + fgets(type, sizeof(type), fp); Please check the return value of fgets. > + fclose(fp); > + > + len = strlen(type); Before passing to strlen, is "type" always guaranteed to have a terminating '\0' character? > + if (len) { > + type[len - 1] = '\0'; > + if (!strcmp(type, "PVH")) { > + return true; > + } > + } > + return false; > +} > + > +static int xen_pt_map_pirq_for_gsi(PCIDevice *d, int *pirq) > +{ > + int gsi; > + XenPCIPassthroughState *s = XEN_PT_DEVICE(d); > + > + gsi = xc_pcidev_get_gsi(xen_xc, > + PCI_SBDF(s->real_device.domain, > + s->real_device.bus, > + s->real_device.dev, > + s->real_device.func)); > + if (gsi >= 0) { > + return xc_physdev_map_pirq_gsi(xen_xc, xen_domid, gsi, pirq); > + } > + > + return gsi; > +} > +#endif > + > static void xen_pt_realize(PCIDevice *d, Error **errp) > { > ERRP_GUARD(); > @@ -847,7 +891,16 @@ static void xen_pt_realize(PCIDevice *d, Error **errp) > goto out; > } > > +#if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 42000 > + if (xen_pt_need_gsi()) { > + rc = xen_pt_map_pirq_for_gsi(d, &pirq); > + } else { > + rc = xc_physdev_map_pirq(xen_xc, xen_domid, machine_irq, &pirq); > + } > +#else > rc = xc_physdev_map_pirq(xen_xc, xen_domid, machine_irq, &pirq); > +#endif > + > if (rc < 0) { > XEN_PT_ERR(d, "Mapping machine irq %u to pirq %i failed, (err: %d)\n", > machine_irq, pirq, errno); > diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h > index eb26cac81098..07805aa8a5f3 100644 > --- a/include/hw/pci/pci.h > +++ b/include/hw/pci/pci.h > @@ -23,6 +23,10 @@ extern bool pci_available; > #define PCI_SLOT_MAX 32 > #define PCI_FUNC_MAX 8 > > +#define PCI_SBDF(seg, bus, dev, func) \ > + ((((uint32_t)(seg)) << 16) | \ > + (PCI_BUILD_BDF(bus, PCI_DEVFN(dev, func)))) > + > /* Class, Vendor and Device IDs from Linux's pci_ids.h */ > #include "hw/pci/pci_ids.h" >
On 2024/11/1 21:09, Stewart Hildebrand wrote: > On 10/24/24 05:06, Jiqian Chen wrote: >> diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c >> index 3635d1b39f79..5b10d501d566 100644 >> --- a/hw/xen/xen_pt.c >> +++ b/hw/xen/xen_pt.c >> @@ -766,6 +766,50 @@ static void xen_pt_destroy(PCIDevice *d) { >> } >> /* init */ >> >> +#if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 42000 >> +static bool xen_pt_need_gsi(void) >> +{ >> + FILE *fp; >> + int len; >> + char type[10]; > > A brief in-code comment to explain how you arrived at 10 would be > appreciated. The max number of characters in the description of the "guest_type" is 4 ("PVH" plus line break). I set it to 10 to prevent longer description types in the future. Do you have another suggest number? > >> + const char *guest_type = "/sys/hypervisor/guest_type"; >> + >> + fp = fopen(guest_type, "r"); >> + if (fp == NULL) { >> + error_report("Cannot open %s: %s", guest_type, strerror(errno)); >> + return false; >> + } >> + fgets(type, sizeof(type), fp); > > Please check the return value of fgets. Will change in next version. > >> + fclose(fp); >> + >> + len = strlen(type); > > Before passing to strlen, is "type" always guaranteed to have a > terminating '\0' character? Yes, "fgets" will guarantee that, and I will add check for "fgets" when it returns NULL in next version. > >> + if (len) { >> + type[len - 1] = '\0'; >> + if (!strcmp(type, "PVH")) { >> + return true; >> + } >> + } >> + return false; >> +} >> + >> +static int xen_pt_map_pirq_for_gsi(PCIDevice *d, int *pirq) >> +{ >> + int gsi; >> + XenPCIPassthroughState *s = XEN_PT_DEVICE(d); >> + >> + gsi = xc_pcidev_get_gsi(xen_xc, >> + PCI_SBDF(s->real_device.domain, >> + s->real_device.bus, >> + s->real_device.dev, >> + s->real_device.func)); >> + if (gsi >= 0) { >> + return xc_physdev_map_pirq_gsi(xen_xc, xen_domid, gsi, pirq); >> + } >> + >> + return gsi; >> +} >> +#endif >> + >> static void xen_pt_realize(PCIDevice *d, Error **errp) >> { >> ERRP_GUARD(); >> @@ -847,7 +891,16 @@ static void xen_pt_realize(PCIDevice *d, Error **errp) >> goto out; >> } >> >> +#if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 42000 >> + if (xen_pt_need_gsi()) { >> + rc = xen_pt_map_pirq_for_gsi(d, &pirq); >> + } else { >> + rc = xc_physdev_map_pirq(xen_xc, xen_domid, machine_irq, &pirq); >> + } >> +#else >> rc = xc_physdev_map_pirq(xen_xc, xen_domid, machine_irq, &pirq); >> +#endif >> + >> if (rc < 0) { >> XEN_PT_ERR(d, "Mapping machine irq %u to pirq %i failed, (err: %d)\n", >> machine_irq, pirq, errno); >> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h >> index eb26cac81098..07805aa8a5f3 100644 >> --- a/include/hw/pci/pci.h >> +++ b/include/hw/pci/pci.h >> @@ -23,6 +23,10 @@ extern bool pci_available; >> #define PCI_SLOT_MAX 32 >> #define PCI_FUNC_MAX 8 >> >> +#define PCI_SBDF(seg, bus, dev, func) \ >> + ((((uint32_t)(seg)) << 16) | \ >> + (PCI_BUILD_BDF(bus, PCI_DEVFN(dev, func)))) >> + >> /* Class, Vendor and Device IDs from Linux's pci_ids.h */ >> #include "hw/pci/pci_ids.h" >> >
On 11/4/24 01:03, Chen, Jiqian wrote: > On 2024/11/1 21:09, Stewart Hildebrand wrote: >> On 10/24/24 05:06, Jiqian Chen wrote: >>> diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c >>> index 3635d1b39f79..5b10d501d566 100644 >>> --- a/hw/xen/xen_pt.c >>> +++ b/hw/xen/xen_pt.c >>> @@ -766,6 +766,50 @@ static void xen_pt_destroy(PCIDevice *d) { >>> } >>> /* init */ >>> >>> +#if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 42000 >>> +static bool xen_pt_need_gsi(void) >>> +{ >>> + FILE *fp; >>> + int len; >>> + char type[10]; >> >> A brief in-code comment to explain how you arrived at 10 would be >> appreciated. > The max number of characters in the description of the "guest_type" is 4 ("PVH" plus line break). > I set it to 10 to prevent longer description types in the future. > Do you have another suggest number? No, I think 10 is a good choice. I'm just looking for the rationale to be documented.
diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c index 3635d1b39f79..5b10d501d566 100644 --- a/hw/xen/xen_pt.c +++ b/hw/xen/xen_pt.c @@ -766,6 +766,50 @@ static void xen_pt_destroy(PCIDevice *d) { } /* init */ +#if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 42000 +static bool xen_pt_need_gsi(void) +{ + FILE *fp; + int len; + char type[10]; + const char *guest_type = "/sys/hypervisor/guest_type"; + + fp = fopen(guest_type, "r"); + if (fp == NULL) { + error_report("Cannot open %s: %s", guest_type, strerror(errno)); + return false; + } + fgets(type, sizeof(type), fp); + fclose(fp); + + len = strlen(type); + if (len) { + type[len - 1] = '\0'; + if (!strcmp(type, "PVH")) { + return true; + } + } + return false; +} + +static int xen_pt_map_pirq_for_gsi(PCIDevice *d, int *pirq) +{ + int gsi; + XenPCIPassthroughState *s = XEN_PT_DEVICE(d); + + gsi = xc_pcidev_get_gsi(xen_xc, + PCI_SBDF(s->real_device.domain, + s->real_device.bus, + s->real_device.dev, + s->real_device.func)); + if (gsi >= 0) { + return xc_physdev_map_pirq_gsi(xen_xc, xen_domid, gsi, pirq); + } + + return gsi; +} +#endif + static void xen_pt_realize(PCIDevice *d, Error **errp) { ERRP_GUARD(); @@ -847,7 +891,16 @@ static void xen_pt_realize(PCIDevice *d, Error **errp) goto out; } +#if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 42000 + if (xen_pt_need_gsi()) { + rc = xen_pt_map_pirq_for_gsi(d, &pirq); + } else { + rc = xc_physdev_map_pirq(xen_xc, xen_domid, machine_irq, &pirq); + } +#else rc = xc_physdev_map_pirq(xen_xc, xen_domid, machine_irq, &pirq); +#endif + if (rc < 0) { XEN_PT_ERR(d, "Mapping machine irq %u to pirq %i failed, (err: %d)\n", machine_irq, pirq, errno); diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h index eb26cac81098..07805aa8a5f3 100644 --- a/include/hw/pci/pci.h +++ b/include/hw/pci/pci.h @@ -23,6 +23,10 @@ extern bool pci_available; #define PCI_SLOT_MAX 32 #define PCI_FUNC_MAX 8 +#define PCI_SBDF(seg, bus, dev, func) \ + ((((uint32_t)(seg)) << 16) | \ + (PCI_BUILD_BDF(bus, PCI_DEVFN(dev, func)))) + /* Class, Vendor and Device IDs from Linux's pci_ids.h */ #include "hw/pci/pci_ids.h"