Commit 7b39b6c7 authored by Sean Christopherson's avatar Sean Christopherson
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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: default avatarSean Christopherson <seanjc@google.com>
parent 66507118

tools/testing/selftests/kvm/include/x86/processor.h

+6 −0
Original line number Diff line number Diff line
@@ -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

tools/testing/selftests/kvm/lib/x86/processor.c

+1 −1
Original line number Diff line number Diff line
@@ -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;