| Message ID | 20181210035825.29404-8-sjitindarsingh@gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | KVM: PPC: Implement passthrough of emulated devices for nested guests | expand |
On Mon, Dec 10, 2018 at 02:58:24PM +1100, Suraj Jitindar Singh wrote: > A guest cannot access quadrants 1 or 2 as this would result in an > exception. Thus introduce the hcall H_COPY_TOFROM_GUEST to be used by a > guest when it wants to perform an access to quadrants 1 or 2, for > example when it wants to access memory for one of its nested guests. > > Also provide an implementation for the kvm-hv module. > > Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com> [snip] > /* > + * Handle the H_COPY_TOFROM_GUEST hcall. > + * r4 = L1 lpid of nested guest > + * r5 = pid > + * r6 = eaddr to access > + * r7 = to buffer (L1 gpa) > + * r8 = from buffer (L1 gpa) Comment says these are GPAs... > + * r9 = n bytes to copy > + */ > +long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu) > +{ > + struct kvm_nested_guest *gp; > + int l1_lpid = kvmppc_get_gpr(vcpu, 4); > + int pid = kvmppc_get_gpr(vcpu, 5); > + gva_t eaddr = kvmppc_get_gpr(vcpu, 6); > + void *gp_to = (void *) kvmppc_get_gpr(vcpu, 7); > + void *gp_from = (void *) kvmppc_get_gpr(vcpu, 8); > + void *buf; > + unsigned long n = kvmppc_get_gpr(vcpu, 9); > + bool is_load = !!gp_to; > + long rc; > + > + if (gp_to && gp_from) /* One must be NULL to determine the direction */ > + return H_PARAMETER; > + > + if (eaddr & (0xFFFUL << 52)) > + return H_PARAMETER; > + > + buf = kzalloc(n, GFP_KERNEL); > + if (!buf) > + return H_NO_MEM; > + > + gp = kvmhv_get_nested(vcpu->kvm, l1_lpid, false); > + if (!gp) { > + rc = H_PARAMETER; > + goto out_free; > + } > + > + mutex_lock(&gp->tlb_lock); > + > + if (is_load) { > + /* Load from the nested guest into our buffer */ > + rc = __kvmhv_copy_tofrom_guest_radix(gp->shadow_lpid, pid, > + eaddr, buf, NULL, n); > + if (rc) > + goto not_found; > + > + /* Write what was loaded into our buffer back to the L1 guest */ > + rc = kvmppc_st(vcpu, (ulong *) &gp_to, n, buf, true); but using kvmppc_st implies that it is an EA (and in fact when you call it in the next patch you pass an EA). It would be more like other hcalls to pass a GPA, meaning that you would use kvm_write_guest() here. On the other hand, with the quadrant access, kvmppc_st() might well be faster than kvm_write_guest. So you need to decide which it is and either fix the comment or change the code. Paul.
On Thu, 2018-12-13 at 16:24 +1100, Paul Mackerras wrote: > On Mon, Dec 10, 2018 at 02:58:24PM +1100, Suraj Jitindar Singh wrote: > > A guest cannot access quadrants 1 or 2 as this would result in an > > exception. Thus introduce the hcall H_COPY_TOFROM_GUEST to be used > > by a > > guest when it wants to perform an access to quadrants 1 or 2, for > > example when it wants to access memory for one of its nested > > guests. > > > > Also provide an implementation for the kvm-hv module. > > > > Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com> > > [snip] > > > /* > > + * Handle the H_COPY_TOFROM_GUEST hcall. > > + * r4 = L1 lpid of nested guest > > + * r5 = pid > > + * r6 = eaddr to access > > + * r7 = to buffer (L1 gpa) > > + * r8 = from buffer (L1 gpa) > > Comment says these are GPAs... > > > + * r9 = n bytes to copy > > + */ > > +long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu) > > +{ > > + struct kvm_nested_guest *gp; > > + int l1_lpid = kvmppc_get_gpr(vcpu, 4); > > + int pid = kvmppc_get_gpr(vcpu, 5); > > + gva_t eaddr = kvmppc_get_gpr(vcpu, 6); > > + void *gp_to = (void *) kvmppc_get_gpr(vcpu, 7); > > + void *gp_from = (void *) kvmppc_get_gpr(vcpu, 8); > > + void *buf; > > + unsigned long n = kvmppc_get_gpr(vcpu, 9); > > + bool is_load = !!gp_to; > > + long rc; > > + > > + if (gp_to && gp_from) /* One must be NULL to determine the > > direction */ > > + return H_PARAMETER; > > + > > + if (eaddr & (0xFFFUL << 52)) > > + return H_PARAMETER; > > + > > + buf = kzalloc(n, GFP_KERNEL); > > + if (!buf) > > + return H_NO_MEM; > > + > > + gp = kvmhv_get_nested(vcpu->kvm, l1_lpid, false); > > + if (!gp) { > > + rc = H_PARAMETER; > > + goto out_free; > > + } > > + > > + mutex_lock(&gp->tlb_lock); > > + > > + if (is_load) { > > + /* Load from the nested guest into our buffer */ > > + rc = __kvmhv_copy_tofrom_guest_radix(gp- > > >shadow_lpid, pid, > > + eaddr, buf, > > NULL, n); > > + if (rc) > > + goto not_found; > > + > > + /* Write what was loaded into our buffer back to > > the L1 guest */ > > + rc = kvmppc_st(vcpu, (ulong *) &gp_to, n, buf, > > true); > > but using kvmppc_st implies that it is an EA (and in fact when you > call it in the next patch you pass an EA). > > It would be more like other hcalls to pass a GPA, meaning that you > would use kvm_write_guest() here. On the other hand, with the > quadrant access, kvmppc_st() might well be faster than > kvm_write_guest. > > So you need to decide which it is and either fix the comment or > change > the code. Lets stick with gpa for now then for consistency, with room for optimisation. > > Paul.
diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h index 33a4fc891947..463c63a9fcf1 100644 --- a/arch/powerpc/include/asm/hvcall.h +++ b/arch/powerpc/include/asm/hvcall.h @@ -335,6 +335,7 @@ #define H_SET_PARTITION_TABLE 0xF800 #define H_ENTER_NESTED 0xF804 #define H_TLB_INVALIDATE 0xF808 +#define H_COPY_TOFROM_GUEST 0xF80C /* Values for 2nd argument to H_SET_MODE */ #define H_SET_MODE_RESOURCE_SET_CIABR 1 diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h index ea94110bfde4..720483733bb2 100644 --- a/arch/powerpc/include/asm/kvm_book3s.h +++ b/arch/powerpc/include/asm/kvm_book3s.h @@ -188,6 +188,9 @@ extern int kvmppc_book3s_hcall_implemented(struct kvm *kvm, unsigned long hc); extern int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, unsigned long ea, unsigned long dsisr); +extern unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid, + gva_t eaddr, void *to, void *from, + unsigned long n); extern long kvmhv_copy_from_guest_radix(struct kvm_vcpu *vcpu, gva_t eaddr, void *to, unsigned long n); extern long kvmhv_copy_to_guest_radix(struct kvm_vcpu *vcpu, gva_t eaddr, @@ -302,6 +305,7 @@ long kvmhv_nested_init(void); void kvmhv_nested_exit(void); void kvmhv_vm_nested_init(struct kvm *kvm); long kvmhv_set_partition_table(struct kvm_vcpu *vcpu); +long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu); void kvmhv_set_ptbl_entry(unsigned int lpid, u64 dw0, u64 dw1); void kvmhv_release_all_nested(struct kvm *kvm); long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu); diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c index e1e3ef710bd0..da89d10e5886 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c @@ -29,9 +29,9 @@ */ static int p9_supported_radix_bits[4] = { 5, 9, 9, 13 }; -static unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid, - gva_t eaddr, void *to, void *from, - unsigned long n) +unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid, + gva_t eaddr, void *to, void *from, + unsigned long n) { unsigned long quadrant, ret = n; int old_pid, old_lpid; @@ -82,6 +82,7 @@ static unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid, return ret; } +EXPORT_SYMBOL_GPL(__kvmhv_copy_tofrom_guest_radix); static long kvmhv_copy_tofrom_guest_radix(struct kvm_vcpu *vcpu, gva_t eaddr, void *to, void *from, unsigned long n) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 2280bc4778f5..bd07f9b7c5e8 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -996,7 +996,11 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu) if (nesting_enabled(vcpu->kvm)) ret = kvmhv_do_nested_tlbie(vcpu); break; - + case H_COPY_TOFROM_GUEST: + ret = H_FUNCTION; + if (nesting_enabled(vcpu->kvm)) + ret = kvmhv_copy_tofrom_guest_nested(vcpu); + break; default: return RESUME_HOST; } diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c index 991f40ce4eea..f54301fcfbe4 100644 --- a/arch/powerpc/kvm/book3s_hv_nested.c +++ b/arch/powerpc/kvm/book3s_hv_nested.c @@ -462,6 +462,81 @@ long kvmhv_set_partition_table(struct kvm_vcpu *vcpu) } /* + * Handle the H_COPY_TOFROM_GUEST hcall. + * r4 = L1 lpid of nested guest + * r5 = pid + * r6 = eaddr to access + * r7 = to buffer (L1 gpa) + * r8 = from buffer (L1 gpa) + * r9 = n bytes to copy + */ +long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu) +{ + struct kvm_nested_guest *gp; + int l1_lpid = kvmppc_get_gpr(vcpu, 4); + int pid = kvmppc_get_gpr(vcpu, 5); + gva_t eaddr = kvmppc_get_gpr(vcpu, 6); + void *gp_to = (void *) kvmppc_get_gpr(vcpu, 7); + void *gp_from = (void *) kvmppc_get_gpr(vcpu, 8); + void *buf; + unsigned long n = kvmppc_get_gpr(vcpu, 9); + bool is_load = !!gp_to; + long rc; + + if (gp_to && gp_from) /* One must be NULL to determine the direction */ + return H_PARAMETER; + + if (eaddr & (0xFFFUL << 52)) + return H_PARAMETER; + + buf = kzalloc(n, GFP_KERNEL); + if (!buf) + return H_NO_MEM; + + gp = kvmhv_get_nested(vcpu->kvm, l1_lpid, false); + if (!gp) { + rc = H_PARAMETER; + goto out_free; + } + + mutex_lock(&gp->tlb_lock); + + if (is_load) { + /* Load from the nested guest into our buffer */ + rc = __kvmhv_copy_tofrom_guest_radix(gp->shadow_lpid, pid, + eaddr, buf, NULL, n); + if (rc) + goto not_found; + + /* Write what was loaded into our buffer back to the L1 guest */ + rc = kvmppc_st(vcpu, (ulong *) &gp_to, n, buf, true); + if (rc) + goto not_found; + } else { + /* Load the data to be stored from the L1 guest into our buf */ + rc = kvmppc_ld(vcpu, (ulong *) &gp_from, n, buf, true); + if (rc) + goto not_found; + + /* Store from our buffer into the nested guest */ + rc = __kvmhv_copy_tofrom_guest_radix(gp->shadow_lpid, pid, + eaddr, NULL, buf, n); + if (rc) + goto not_found; + } + +out_unlock: + mutex_unlock(&gp->tlb_lock); + kvmhv_put_nested(gp); +out_free: + kfree(buf); + return rc; +not_found: + rc = H_NOT_FOUND; + goto out_unlock; +} + +/* * Reload the partition table entry for a guest. * Caller must hold gp->tlb_lock. */
A guest cannot access quadrants 1 or 2 as this would result in an exception. Thus introduce the hcall H_COPY_TOFROM_GUEST to be used by a guest when it wants to perform an access to quadrants 1 or 2, for example when it wants to access memory for one of its nested guests. Also provide an implementation for the kvm-hv module. Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com> --- arch/powerpc/include/asm/hvcall.h | 1 + arch/powerpc/include/asm/kvm_book3s.h | 4 ++ arch/powerpc/kvm/book3s_64_mmu_radix.c | 7 ++-- arch/powerpc/kvm/book3s_hv.c | 6 ++- arch/powerpc/kvm/book3s_hv_nested.c | 75 ++++++++++++++++++++++++++++++++++ 5 files changed, 89 insertions(+), 4 deletions(-)