Hi Christoffer, > -----Original Message----- > From: kvmarm-bounces@xxxxxxxxxxxxxxxxxxxxx [mailto:kvmarm- > bounces@xxxxxxxxxxxxxxxxxxxxx] On Behalf Of Christoffer Dall > Sent: Monday, July 16, 2018 6:36 PM > To: kvmarm@xxxxxxxxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Cc: kvm@xxxxxxxxxxxxxxx; Marc Zyngier <marc.zyngier@xxxxxxx>; Andre > Przywara <andre.przywara@xxxxxxx> > Subject: [PATCH v4 07/10] KVM: arm/arm64: vgic: Return error on > incompatible uaccess GICD_IIDR writes > > If userspace attempts to write a GICD_IIDR that does not match the > kernel version, return an error to userspace. The intention is to allow > implementation changes inside KVM while avoiding silently breaking > migration resulting in guests not running without any clear indication > of what went wrong. > > Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxx> > --- > virt/kvm/arm/vgic/vgic-mmio-v2.c | 21 ++++++++++++++++++--- > virt/kvm/arm/vgic/vgic-mmio-v3.c | 21 ++++++++++++++++++--- > 2 files changed, 36 insertions(+), 6 deletions(-) > > diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic- > mmio-v2.c > index db646f1..4f0f2c4 100644 > --- a/virt/kvm/arm/vgic/vgic-mmio-v2.c > +++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c > @@ -75,6 +75,20 @@ static void vgic_mmio_write_v2_misc(struct kvm_vcpu > *vcpu, > } > } > > +static int vgic_mmio_uaccess_write_v2_misc(struct kvm_vcpu *vcpu, > + gpa_t addr, unsigned int len, > + unsigned long val) > +{ > + switch (addr & 0x0c) { I am just understanding the code, not sure if it make sense to replace hardcoded "0x0c". Thanks -Bharat > + case GIC_DIST_IIDR: > + if (val != vgic_mmio_read_v2_misc(vcpu, addr, len)) > + return -EINVAL; > + } > + > + vgic_mmio_write_v2_misc(vcpu, addr, len, val); > + return 0; > +} > + > static void vgic_mmio_write_sgir(struct kvm_vcpu *source_vcpu, > gpa_t addr, unsigned int len, > unsigned long val) > @@ -367,9 +381,10 @@ static void vgic_mmio_write_apr(struct kvm_vcpu > *vcpu, > } > > static const struct vgic_register_region vgic_v2_dist_registers[] = { > - REGISTER_DESC_WITH_LENGTH(GIC_DIST_CTRL, > - vgic_mmio_read_v2_misc, vgic_mmio_write_v2_misc, 12, > - VGIC_ACCESS_32bit), > + REGISTER_DESC_WITH_LENGTH_UACCESS(GIC_DIST_CTRL, > + vgic_mmio_read_v2_misc, vgic_mmio_write_v2_misc, > + NULL, vgic_mmio_uaccess_write_v2_misc, > + 12, VGIC_ACCESS_32bit), > REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_IGROUP, > vgic_mmio_read_raz, vgic_mmio_write_wi, NULL, NULL, 1, > VGIC_ACCESS_32bit), > diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic- > mmio-v3.c > index ef57a1a..abdb0ec 100644 > --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c > +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c > @@ -113,6 +113,20 @@ static void vgic_mmio_write_v3_misc(struct > kvm_vcpu *vcpu, > } > } > > +static int vgic_mmio_uaccess_write_v3_misc(struct kvm_vcpu *vcpu, > + gpa_t addr, unsigned int len, > + unsigned long val) > +{ > + switch (addr & 0x0c) { > + case GICD_IIDR: > + if (val != vgic_mmio_read_v3_misc(vcpu, addr, len)) > + return -EINVAL; > + } > + > + vgic_mmio_write_v3_misc(vcpu, addr, len, val); > + return 0; > +} > + > static unsigned long vgic_mmio_read_irouter(struct kvm_vcpu *vcpu, > gpa_t addr, unsigned int len) > { > @@ -449,9 +463,10 @@ static void vgic_mmio_write_pendbase(struct > kvm_vcpu *vcpu, > } > > static const struct vgic_register_region vgic_v3_dist_registers[] = { > - REGISTER_DESC_WITH_LENGTH(GICD_CTLR, > - vgic_mmio_read_v3_misc, vgic_mmio_write_v3_misc, 16, > - VGIC_ACCESS_32bit), > + REGISTER_DESC_WITH_LENGTH_UACCESS(GICD_CTLR, > + vgic_mmio_read_v3_misc, vgic_mmio_write_v3_misc, > + NULL, vgic_mmio_uaccess_write_v3_misc, > + 16, VGIC_ACCESS_32bit), > REGISTER_DESC_WITH_LENGTH(GICD_STATUSR, > vgic_mmio_read_rao, vgic_mmio_write_wi, 4, > VGIC_ACCESS_32bit), > -- > 2.7.4 > > _______________________________________________ > kvmarm mailing list > kvmarm@xxxxxxxxxxxxxxxxxxxxx > https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flist > s.cs.columbia.edu%2Fmailman%2Flistinfo%2Fkvmarm&data=02%7C01% > 7Cbharat.bhushan%40nxp.com%7Cf2d3e98a8d1a48166ce108d5eb1d06f4%7C > 686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C636673432268886197&am > p;sdata=DitjaxtCqfVUge823Qw9IpT%2Fg9EoN2xI%2FIlj6mCdZ9k%3D&r > eserved=0
