| Message ID | 20200701140206.8664-1-graf@amazon.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 731532176716e2775a5d21115bb9c5c61e0cb704 |
| Headers | show |
| Series | KVM: arm64: Change default caching mode for {PEND, PROP}BASER.outer | expand |
On Wed, 01 Jul 2020 15:02:06 +0100, Alexander Graf <graf@amazon.com> wrote: > > PENDBASER and PROPBASER define the outer caching mode for LPI tables. > The memory backing them may not be outer sharable, so we mark them as nC > by default. This however, breaks Windows on ARM which only accepts > SameAsInner or RaWaWb as values for outer cachability. > > We do today already allow the outer mode to be set to SameAsInner > explicitly, so the easy fix is to default to that instead of nC for > situations when an OS asks for a not fulfillable cachability request. > > This fixes booting Windows in KVM with vgicv3 and ITS enabled for me. > > Signed-off-by: Alexander Graf <graf@amazon.com> > --- > arch/arm64/kvm/vgic/vgic-mmio-v3.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c > index d2339a2b9fb9..5c786b915cd3 100644 > --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c > +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c > @@ -389,7 +389,7 @@ u64 vgic_sanitise_outer_cacheability(u64 field) > case GIC_BASER_CACHE_nC: > return field; > default: > - return GIC_BASER_CACHE_nC; > + return GIC_BASER_CACHE_SameAsInner; > } > } > I am going to provisionally queue this for 5.9, with the explicit reserve that it will be reverted if it causes a regression for other guests (as this is an observable change in behaviour). Thanks, M.
On Wed, 1 Jul 2020 16:02:06 +0200, Alexander Graf wrote: > PENDBASER and PROPBASER define the outer caching mode for LPI tables. > The memory backing them may not be outer sharable, so we mark them as nC > by default. This however, breaks Windows on ARM which only accepts > SameAsInner or RaWaWb as values for outer cachability. > > We do today already allow the outer mode to be set to SameAsInner > explicitly, so the easy fix is to default to that instead of nC for > situations when an OS asks for a not fulfillable cachability request. > > [...] Applied to kvm-arm64/next-5.9, thanks! [1/1] KVM: arm64: vgic-its: Change default outer cacheability for {PEND, PROP}BASER commit: 731532176716e2775a5d21115bb9c5c61e0cb704 Cheers, M.
diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c index d2339a2b9fb9..5c786b915cd3 100644 --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c @@ -389,7 +389,7 @@ u64 vgic_sanitise_outer_cacheability(u64 field) case GIC_BASER_CACHE_nC: return field; default: - return GIC_BASER_CACHE_nC; + return GIC_BASER_CACHE_SameAsInner; } }
PENDBASER and PROPBASER define the outer caching mode for LPI tables. The memory backing them may not be outer sharable, so we mark them as nC by default. This however, breaks Windows on ARM which only accepts SameAsInner or RaWaWb as values for outer cachability. We do today already allow the outer mode to be set to SameAsInner explicitly, so the easy fix is to default to that instead of nC for situations when an OS asks for a not fulfillable cachability request. This fixes booting Windows in KVM with vgicv3 and ITS enabled for me. Signed-off-by: Alexander Graf <graf@amazon.com> --- arch/arm64/kvm/vgic/vgic-mmio-v3.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)