[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 3/4] x86/nvmx: split updating RVI from SVI in nvmx_update_apicv
> From: Roger Pau Monne <roger.pau@xxxxxxxxxx> > Sent: Thursday, March 26, 2020 11:27 PM > > Updating SVI is required when an interrupt has been injected using the > Ack on exit VMEXIT feature, so that the in service interrupt in the > GUEST_INTR_STATUS matches the vector that is signaled in > VM_EXIT_INTR_INFO. > > Updating RVI however is not tied to the Ack on exit feature, as it > signals the next vector to be injected, and hence should always be > updated to the next pending vector, regardless of whether Ack on exit > is enabled. > > When not using the Ack on exit feature preserve the previous vector in > SVI, so that it's not lost when RVI is updated to contain the pending > vector to inject. > > Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx> Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>, with one small comment: > --- > Changes since v2: > - Return early if the exit reason != EXTERNAL_INTERRUPT. > - Reduce the number of vmwrites by accumulating the changes to a > local variable which is flushed at the end of the function. > - Attempt to preserve the exiting SVI if Ack on exit is not enabled. > --- > xen/arch/x86/hvm/vmx/vvmx.c | 33 ++++++++++++++++++++++++--------- > 1 file changed, 24 insertions(+), 9 deletions(-) > > diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c > index 1753005c91..39fb553590 100644 > --- a/xen/arch/x86/hvm/vmx/vvmx.c > +++ b/xen/arch/x86/hvm/vmx/vvmx.c > @@ -1384,28 +1384,43 @@ static void nvmx_update_apicv(struct vcpu *v) > struct nestedvmx *nvmx = &vcpu_2_nvmx(v); > unsigned long reason = get_vvmcs(v, VM_EXIT_REASON); > unsigned long intr_info = get_vvmcs(v, VM_EXIT_INTR_INFO); > + unsigned long status; > + int rvi; > > - if ( reason == EXIT_REASON_EXTERNAL_INTERRUPT && > - nvmx->intr.source == hvm_intsrc_lapic && > + if ( reason != EXIT_REASON_EXTERNAL_INTERRUPT ) > + return; can we also exit if source is not lapic? as we discussed in another thread, the whole logic here is only for lapic not others... Thanks Kevin > + > + if ( nvmx->intr.source == hvm_intsrc_lapic && > (intr_info & INTR_INFO_VALID_MASK) ) > { > - uint16_t status; > - uint32_t rvi, ppr; > - uint32_t vector = intr_info & 0xff; > + uint32_t ppr; > + unsigned int vector = intr_info & INTR_INFO_VECTOR_MASK; > struct vlapic *vlapic = vcpu_vlapic(v); > > + /* > + * Update SVI to record the current in service interrupt that's > + * signaled in EXIT_INTR_INFO. > + */ > vlapic_ack_pending_irq(v, vector, 1); > > ppr = vlapic_set_ppr(vlapic); > WARN_ON((ppr & 0xf0) != (vector & 0xf0)); > > status = vector << VMX_GUEST_INTR_STATUS_SVI_OFFSET; > - rvi = vlapic_has_pending_irq(v); > - if ( rvi != -1 ) > - status |= rvi & VMX_GUEST_INTR_STATUS_SUBFIELD_BITMASK; > + } > + else > + /* Keep previous SVI if there's any. */ > + __vmread(GUEST_INTR_STATUS, &status); > > - __vmwrite(GUEST_INTR_STATUS, status); > + rvi = vlapic_has_pending_irq(v); > + if ( rvi != -1 ) > + { > + status &= ~VMX_GUEST_INTR_STATUS_SUBFIELD_BITMASK > + status |= rvi & VMX_GUEST_INTR_STATUS_SUBFIELD_BITMASK; > } > + > + if ( status ) > + __vmwrite(GUEST_INTR_STATUS, status); > } > > static void virtual_vmexit(struct cpu_user_regs *regs) > -- > 2.26.0
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