| Message ID | 1436372356-30410-11-git-send-email-marc.zyngier@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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@arm.com> > --- > 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@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 + 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 + isb + ret + +install_el2_stub: /* Hypervisor stub */ adrp x0, __hyp_stub_vectors add x0, x0, #:lo12:__hyp_stub_vectors
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@arm.com> --- arch/arm64/kernel/head.S | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-)