| Message ID | 20220610110704.29039-1-jane.malalane@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v4] x86/hvm: Widen condition for is_hvm_pv_evtchn_domain() and report fix in CPUID | expand |
On Fri, Jun 10, 2022 at 12:07:04PM +0100, Jane Malalane wrote: > Have is_hvm_pv_evtchn_domain() return true for vector callbacks for > evtchn delivery set up on a per-vCPU basis via > HVMOP_set_evtchn_upcall_vector. > > Assume that if vCPU0 uses HVMOP_set_evtchn_upcall_vector, all > remaining vCPUs will too and thus remove is_hvm_pv_evtchn_vcpu() and > replace sole caller with is_hvm_pv_evtchn_domain(). > > is_hvm_pv_evtchn_domain() returning true is a condition for setting up > physical IRQ to event channel mappings. Therefore, also add a CPUID > bit so that guests know whether the check in is_hvm_pv_evtchn_domain() > will fail when using HVMOP_set_evtchn_upcall_vector. This matters for > guests that route PIRQs over event channels since > is_hvm_pv_evtchn_domain() is a condition in physdev_map_pirq(). > > The naming of the CPUID bit is quite generic about upcall support > being available. That's done so that the define name doesn't become > overly long. > > A guest that doesn't care about physical interrupts routed over event > channels can just test for the availability of the hypercall directly > (HVMOP_set_evtchn_upcall_vector) without checking the CPUID bit. > > Signed-off-by: Jane Malalane <jane.malalane@citrix.com> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> Thanks, Roger.
diff --git a/xen/arch/x86/hvm/irq.c b/xen/arch/x86/hvm/irq.c index 5a7f39b54f..19252448cb 100644 --- a/xen/arch/x86/hvm/irq.c +++ b/xen/arch/x86/hvm/irq.c @@ -325,7 +325,7 @@ void hvm_assert_evtchn_irq(struct vcpu *v) vlapic_set_irq(vcpu_vlapic(v), vector, 0); } - else if ( is_hvm_pv_evtchn_vcpu(v) ) + else if ( is_hvm_pv_evtchn_domain(v->domain) ) vcpu_kick(v); else if ( v->vcpu_id == 0 ) hvm_set_callback_irq_level(v); diff --git a/xen/arch/x86/include/asm/domain.h b/xen/arch/x86/include/asm/domain.h index 35898d725f..dcd221cc6f 100644 --- a/xen/arch/x86/include/asm/domain.h +++ b/xen/arch/x86/include/asm/domain.h @@ -14,9 +14,14 @@ #define has_32bit_shinfo(d) ((d)->arch.has_32bit_shinfo) +/* + * Set to true if either the global vector-type callback or per-vCPU + * LAPIC vectors are used. Assume all vCPUs will use + * HVMOP_set_evtchn_upcall_vector as long as the initial vCPU does. + */ #define is_hvm_pv_evtchn_domain(d) (is_hvm_domain(d) && \ - (d)->arch.hvm.irq->callback_via_type == HVMIRQ_callback_vector) -#define is_hvm_pv_evtchn_vcpu(v) (is_hvm_pv_evtchn_domain(v->domain)) + ((d)->arch.hvm.irq->callback_via_type == HVMIRQ_callback_vector || \ + (d)->vcpu[0]->arch.hvm.evtchn_upcall_vector)) #define is_domain_direct_mapped(d) ((void)(d), 0) #define VCPU_TRAP_NONE 0 diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c index 25bffe47d7..1a7f9df067 100644 --- a/xen/arch/x86/traps.c +++ b/xen/arch/x86/traps.c @@ -1152,6 +1152,12 @@ void cpuid_hypervisor_leaves(const struct vcpu *v, uint32_t leaf, res->a |= XEN_HVM_CPUID_DOMID_PRESENT; res->c = d->domain_id; + /* + * Per-vCPU event channel upcalls are implemented and work + * correctly with PIRQs routed over event channels. + */ + res->a |= XEN_HVM_CPUID_UPCALL_VECTOR; + break; case 5: /* PV-specific parameters */ diff --git a/xen/include/public/arch-x86/cpuid.h b/xen/include/public/arch-x86/cpuid.h index f2b2b3632c..c49eefeaf8 100644 --- a/xen/include/public/arch-x86/cpuid.h +++ b/xen/include/public/arch-x86/cpuid.h @@ -109,6 +109,11 @@ * field from 8 to 15 bits, allowing to target APIC IDs up 32768. */ #define XEN_HVM_CPUID_EXT_DEST_ID (1u << 5) +/* + * Per-vCPU event channel upcalls work correctly with physical IRQs + * bound to event channels. + */ +#define XEN_HVM_CPUID_UPCALL_VECTOR (1u << 6) /* * Leaf 6 (0x40000x05)
Have is_hvm_pv_evtchn_domain() return true for vector callbacks for evtchn delivery set up on a per-vCPU basis via HVMOP_set_evtchn_upcall_vector. Assume that if vCPU0 uses HVMOP_set_evtchn_upcall_vector, all remaining vCPUs will too and thus remove is_hvm_pv_evtchn_vcpu() and replace sole caller with is_hvm_pv_evtchn_domain(). is_hvm_pv_evtchn_domain() returning true is a condition for setting up physical IRQ to event channel mappings. Therefore, also add a CPUID bit so that guests know whether the check in is_hvm_pv_evtchn_domain() will fail when using HVMOP_set_evtchn_upcall_vector. This matters for guests that route PIRQs over event channels since is_hvm_pv_evtchn_domain() is a condition in physdev_map_pirq(). The naming of the CPUID bit is quite generic about upcall support being available. That's done so that the define name doesn't become overly long. A guest that doesn't care about physical interrupts routed over event channels can just test for the availability of the hypercall directly (HVMOP_set_evtchn_upcall_vector) without checking the CPUID bit. Signed-off-by: Jane Malalane <jane.malalane@citrix.com> --- CC: Jan Beulich <jbeulich@suse.com> CC: Andrew Cooper <andrew.cooper3@citrix.com> CC: "Roger Pau Monné" <roger.pau@citrix.com> CC: Wei Liu <wl@xen.org> v4: * Remove is_hvm_pv_evtchn_vcpu and replace sole caller. v3: * Improve commit message and title. v2: * Since the naming of the CPUID bit is quite generic, better explain when it should be checked for, in code comments and commit message. --- xen/arch/x86/hvm/irq.c | 2 +- xen/arch/x86/include/asm/domain.h | 9 +++++++-- xen/arch/x86/traps.c | 6 ++++++ xen/include/public/arch-x86/cpuid.h | 5 +++++ 4 files changed, 19 insertions(+), 3 deletions(-)