Commit d084ecc5 authored by David Brazdil's avatar David Brazdil Committed by Marc Zyngier
Browse files

KVM: arm64: Add offset for hyp VA <-> PA conversion 



Add a host-initialized constant to KVM nVHE hyp code for converting
between EL2 linear map virtual addresses and physical addresses.
Also add `__hyp_pa` macro that performs the conversion.

Signed-off-by: default avatarDavid Brazdil <dbrazdil@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-18-dbrazdil@google.com
parent eeeee719

arch/arm64/kvm/hyp/nvhe/psci-relay.c

+3 −0
Original line number Diff line number Diff line
@@ -18,6 +18,9 @@ 
/* Config options set by the host. */

__ro_after_init u32 kvm_host_psci_version;

__ro_after_init struct psci_0_1_function_ids kvm_host_psci_0_1_function_ids;

__ro_after_init s64 hyp_physvirt_offset;



#define __hyp_pa(x) ((phys_addr_t)((x)) + hyp_physvirt_offset)



static u64 get_psci_func_id(struct kvm_cpu_context *host_ctxt)

{

arch/arm64/kvm/va_layout.c

+27 −3
Original line number Diff line number Diff line
@@ -23,6 +23,30 @@ static u8 tag_lsb; 
static u64 tag_val;

static u64 va_mask;



/*

 * Compute HYP VA by using the same computation as kern_hyp_va().

 */

static u64 __early_kern_hyp_va(u64 addr)

{

	addr &= va_mask;

	addr |= tag_val << tag_lsb;

	return addr;

}



/*

 * Store a hyp VA <-> PA offset into a hyp-owned variable.

 */

static void init_hyp_physvirt_offset(void)

{

	extern s64 kvm_nvhe_sym(hyp_physvirt_offset);

	u64 kern_va, hyp_va;



	/* Compute the offset from the hyp VA and PA of a random symbol. */

	kern_va = (u64)kvm_ksym_ref(__hyp_text_start);

	hyp_va = __early_kern_hyp_va(kern_va);

	CHOOSE_NVHE_SYM(hyp_physvirt_offset) = (s64)__pa(kern_va) - (s64)hyp_va;

}



/*

 * We want to generate a hyp VA with the following format (with V ==

 * vabits_actual):
@@ -54,6 +78,8 @@ __init void kvm_compute_layout(void) 
		tag_val |= get_random_long() & GENMASK_ULL(vabits_actual - 2, tag_lsb);

	}

	tag_val >>= tag_lsb;



	init_hyp_physvirt_offset();

}



static u32 compute_instruction(int n, u32 rd, u32 rn)
@@ -151,9 +177,7 @@ void kvm_patch_vector_branch(struct alt_instr *alt, 
	/*

	 * Compute HYP VA by using the same computation as kern_hyp_va()

	 */

	addr = (uintptr_t)kvm_ksym_ref(__kvm_hyp_vector);

	addr &= va_mask;

	addr |= tag_val << tag_lsb;

	addr = __early_kern_hyp_va((u64)kvm_ksym_ref(__kvm_hyp_vector));



	/* Use PC[10:7] to branch to the same vector in KVM */

	addr |= ((u64)origptr & GENMASK_ULL(10, 7));