On Tue, Aug 25, 2026 at 08:57:31PM -0700, Kishen Maloor wrote: > Date: Tue, 25 Aug 2026 20:57:31 -0700 > From: Kishen Maloor <[email protected]> > Subject: [PATCH 2/5] target/i386: Add LASS support in CR4 > X-Mailer: git-send-email 2.47.1 > > From: Isaku Yamahata <[email protected]> > > CR4.LASS[bit 27] enables Linear Address Space Separation, and may be set > only when CPUID.(EAX=7,ECX=1):EAX[6] enumerates LASS. > > Recognize CR4.LASS as a valid bit by adding CR4_LASS_MASK to the known > bits, i.e. clearing it from CR4_RESERVED_MASK. Mark it reserved in > cr4_reserved_bits() and clear it in cpu_x86_update_cr4() when the guest > CPUID does not enumerate LASS. This keeps CR4 handling consistent on > paths that reach cpu_x86_update_cr4(), such as gdbstub register writes. > > LASS is not emulated by TCG, so it is not added to TCG_7_1_EAX_FEATURES > and cannot be set under TCG (helper_write_crN() and helper_vmrun() both > reject reserved bits via cr4_reserved_bits()). > > Signed-off-by: Isaku Yamahata <[email protected]> > [kishen: rewrote commit message, rebased, fixed formatting] > Signed-off-by: Kishen Maloor <[email protected]> > --- > target/i386/cpu.h | 7 ++++++- > target/i386/helper.c | 4 ++++ > 2 files changed, 10 insertions(+), 1 deletion(-)
Reviewed-by: Zhao Liu <[email protected]>
