From: Sean Christopherson Date: Tue, 9 Sep 2025 20:28:32 +0000 (-0700) Subject: KVM: selftests: Add support for #DE exception fixup X-Git-Tag: v6.18-rc1~95^2~2^2~10 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7b39b6c76942d42d3eecf0844d0f6a76fb64e805;p=thirdparty%2Flinux.git KVM: selftests: Add support for #DE exception fixup Add support for handling #DE (divide error) exceptions in KVM selftests so that the fastops test can verify KVM correctly handles #DE when emulating DIV or IDIV on behalf of the guest. Morph #DE to 0xff (i.e. to -1) as a mostly-arbitrary vector to indicate #DE, so that '0' (the real #DE vector) can still be used to indicate "no exception". Link: https://lore.kernel.org/r/20250909202835.333554-2-seanjc@google.com Signed-off-by: Sean Christopherson --- diff --git a/tools/testing/selftests/kvm/include/x86/processor.h b/tools/testing/selftests/kvm/include/x86/processor.h index 488d516c4f6f0..efcc4b1de523a 100644 --- a/tools/testing/selftests/kvm/include/x86/processor.h +++ b/tools/testing/selftests/kvm/include/x86/processor.h @@ -1179,6 +1179,12 @@ struct idt_entry { void vm_install_exception_handler(struct kvm_vm *vm, int vector, void (*handler)(struct ex_regs *)); +/* + * Exception fixup morphs #DE to an arbitrary magic vector so that '0' can be + * used to signal "no expcetion". + */ +#define KVM_MAGIC_DE_VECTOR 0xff + /* If a toddler were to say "abracadabra". */ #define KVM_EXCEPTION_MAGIC 0xabacadabaULL diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c index d4c19ac885a95..3b63c99f7b963 100644 --- a/tools/testing/selftests/kvm/lib/x86/processor.c +++ b/tools/testing/selftests/kvm/lib/x86/processor.c @@ -557,7 +557,7 @@ static bool kvm_fixup_exception(struct ex_regs *regs) return false; if (regs->vector == DE_VECTOR) - return false; + regs->vector = KVM_MAGIC_DE_VECTOR; regs->rip = regs->r11; regs->r9 = regs->vector;