Re: [PATCH 05/16] KVM: arm64: Plumb MMIO checking into the fault handling
From: Will Deacon <will@kernel.org>
Date: 2021-07-27 18:11:28
Also in:
kvm, kvmarm, lkml
On Thu, Jul 15, 2021 at 05:31:48PM +0100, Marc Zyngier wrote:
Plumb the MMIO checking code into the MMIO fault handling code. Nothing allows a region to be registered yet, so there should be no funtional change either.
Typo: functional
quoted hunk ↗ jump to hunk
Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/kvm/mmio.c | 10 ++++++++++ 1 file changed, 10 insertions(+)diff --git a/arch/arm64/kvm/mmio.c b/arch/arm64/kvm/mmio.c index 3dd38a151d2a..fd5747279d27 100644 --- a/arch/arm64/kvm/mmio.c +++ b/arch/arm64/kvm/mmio.c@@ -6,6 +6,7 @@ #include <linux/kvm_host.h> #include <asm/kvm_emulate.h> +#include <asm/kvm_mmu.h> #include <trace/events/kvm.h> #include "trace.h"@@ -130,6 +131,10 @@ int io_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa) int len; u8 data_buf[8]; + /* Check failed? Return to the guest for debriefing... */ + if (!kvm_check_ioguard_page(vcpu, fault_ipa)) + return 1; + /* * No valid syndrome? Ask userspace for help if it has * volunteered to do so, and bail out otherwise.@@ -156,6 +161,11 @@ int io_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa) len = kvm_vcpu_dabt_get_as(vcpu); rt = kvm_vcpu_dabt_get_rd(vcpu); + /* If we cross a page boundary, check that too... */ + if (((fault_ipa + len - 1) & PAGE_MASK) != (fault_ipa & PAGE_MASK) && + !kvm_check_ioguard_page(vcpu, fault_ipa + len - 1)) + return 1; +
I find this a little odd as the checks straddle the invalid syndrome check, meaning that the relative priorities of KVM_ARCH_FLAG_MMIO_GUARD and KVM_ARCH_FLAG_RETURN_NISV_IO_ABORT_TO_USER are unclear. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel