Re: [PATCH v3 2/6] KVM: x86: add force_intercept_exceptions_mask
From: Sean Christopherson <seanjc@google.com>
Date: 2021-09-02 16:56:59
Also in:
kvm, linux-kselftest, lkml
Assuming this hasn't been abandoned... On Wed, Aug 11, 2021, Maxim Levitsky wrote:
quoted hunk ↗ jump to hunk
This parameter will be used by VMX and SVM code to force interception of a set of exceptions, given by a bitmask for guest debug and/or kvm debug. This is based on an idea first shown here: https://patchwork.kernel.org/project/kvm/patch/20160301192822.GD22677@pd.tnic/ CC: Borislav Petkov <redacted> Signed-off-by: Maxim Levitsky <redacted> --- arch/x86/kvm/x86.c | 3 +++ arch/x86/kvm/x86.h | 2 ++ 2 files changed, 5 insertions(+)diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index fdc0c18339fb..092e2fad3c0d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c@@ -184,6 +184,9 @@ module_param(force_emulation_prefix, bool, S_IRUGO); int __read_mostly pi_inject_timer = -1; module_param(pi_inject_timer, bint, S_IRUGO | S_IWUSR); +uint force_intercept_exceptions_mask; +module_param(force_intercept_exceptions_mask, uint, S_IRUGO | S_IWUSR);
Use octal permissions. This also can't be a simple writable param, at least not without a well-documented disclaimer, as there's no guarantee a vCPU will update its exception bitmap in a timely fashion. An alternative to a module param would be to extend/add a per-VM ioctl(), e.g. maybe KVM_SET_GUEST_DEBUG? The downside of an ioctl() is that it would require userspace enabling :-/