On Wed, Jul 08, 2015 at 05:19:13PM +0100, Marc Zyngier wrote: > With the ARMv8.1 VHE, the architecture is able to (almost) transparently > run the kernel at EL2, despite being written for EL1. > > This patch takes care of the "almost" part, mostly preventing the kernel > from dropping from EL2 to EL1, and setting up the HYP configuration. > > Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> > --- > arch/arm64/kernel/head.S | 23 ++++++++++++++++++++++- > 1 file changed, 22 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S > index c0ff3ce..a179747 100644 > --- a/arch/arm64/kernel/head.S > +++ b/arch/arm64/kernel/head.S > @@ -29,6 +29,7 @@ > #include <asm/asm-offsets.h> > #include <asm/cache.h> > #include <asm/cputype.h> > +#include <asm/kvm_mmu.h> > #include <asm/memory.h> > #include <asm/thread_info.h> > #include <asm/pgtable-hwdef.h> > @@ -481,8 +482,16 @@ CPU_LE( bic x0, x0, #(3 << 24) ) // Clear the EE and E0E bits for EL1 > isb > ret > > + /* Check for VHE being present */ > +2: mrs x2, id_aa64mmfr1_el1 > + ubfx x2, x2, #8, #4 > + > /* Hyp configuration. */ > -2: mov x0, #(1 << 31) // 64-bit EL1 > + mov x0, #HCR_RW // 64-bit EL1 > + cbz x2, set_hcr > + orr x0, x0, #HCR_TGE // Enable Host Extensions > + orr x0, x0, #HCR_E2H > +set_hcr: > msr hcr_el2, x0 > > /* Generic timers. */ > @@ -522,6 +531,9 @@ CPU_LE( movk x0, #0x30d0, lsl #16 ) // Clear EE and E0E on LE systems > > /* Coprocessor traps. */ > mov x0, #0x33ff These bits are RES0 with VHE enabled, afaict. > + cbz x2, set_cptr > + orr x0, x0, #(3 << 20) // Don't trap FP > +set_cptr: > msr cptr_el2, x0 // Disable copro. traps to EL2 > > #ifdef CONFIG_COMPAT > @@ -531,6 +543,15 @@ CPU_LE( movk x0, #0x30d0, lsl #16 ) // Clear EE and E0E on LE systems > /* Stage-2 translation */ > msr vttbr_el2, xzr > > + cbz x2, install_el2_stub > + > + setup_vtcr x4, x5 > + > + mov w20, #BOOT_CPU_MODE_EL2 // This CPU booted in EL2 You do this in install_el2_stub as well -- can you move it above the cbz? Will -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
